electrometer as subsequently improved by Becquerel, and states that Mr.
Sturgeon describes (“Lectures on Galvanism,” 1843) a somewhat similar
arrangement, the delicacy of which he states to be such that the cap
(plate) being of zinc and of the size of a sixpence, the pendant leaf
is caused to lean toward the negative pole by merely pressing a plate
of copper, also the size of a sixpence, upon it, and when the copper is
suddenly lifted up the leaf strikes. The different electrical states of
the inside and outside of various articles of clothing were readily
ascertained by this delicate electroscope.
M. Gottlieb Christian Bohnenberger, of Neuenberg (1732–1807), is
the author of several works treating particularly of the electrical
machine, the electric spark, the electric doubler, etc., published at
Stuttgart between 1784 and 1798.
REFERENCES.--“La Grande Encyclopédie,” Vol. VII. p. 84; L. W.
Gilbert, _Annalen der Physik_, Vols. XXIII (for Behrend’s);
XLIX, LI (for “Beschreibung ... empfindlichen elektrometers
...”); _Annales de Chimie et de Physique_, Vol. XVI. p. 91; J.
C. Poggendorff, “Biogr.-Liter. Handwörterbuch ...” Vol. I. p.
226; _Sci. Am. Supp._, No. 519, p. 8290, for Pouillet’s remarks
upon the effectiveness of dry pile electroscopes; De la Rive,
“Treatise on Electricity,” Vol. I. pp. 54–56.
=A.D. 1815.=--Mr. B. M. Forster sends to the _Philosophical
Magazine_ (Vol. XLVII. pp. 344–345) the description of an electrical
instrument called “The Thunderstorm Alarum,” which can be made to
show the effect produced by the passage of a charged cloud over an
_atmospherical electrometer_.
He had several years before described, at p. 205 of the same
publication, a method of fitting up in portable form one of De Luc’s
electrical columns, respecting which latter he subsequently addressed
communications, which appeared in Vols. XXXV. pp. 317, 399, 468; XXXVI.
pp. 74, 317, 472; XXXVII. pp. 197, 265, also relative to one which he
constructed and which ran continuously for five months.
REFERENCES.--_Phil. Mag._, Vol. IV for 1828, p. 463; eighth
“Britannica,” Vol. XXI. p. 619.
=A.D. 1815.=--Gregory (Olinthus Gilbert), LL.D., Professor of
Mathematics at the Royal Military Academy, Woolwich, in his “Treatise
on Mechanics,” London, 1815 (Vol. II. pp. 442–449), describes the
methods of transmitting distant signals introduced by Polybius, the
Marquis of Worcester, Robert Hooke, Amontons and Chappe, and alludes to
an improved telegraph described in the “Gentleman’s Magazine,” as well
as to the so-called nocturnal telegraph, of which an account is to be
found in the _Repertory of the Arts and Manufactures_ (“Biographie
Générale,” Tome XXI. p. 903).
=A.D. 1815.=--In the _Philosophical Magazine_ (Vol. XLVI. pp. 161,
259), will be found an account of the electrical experiments of M. De
Nelis, of Mechlin, or Malines, in the Netherlands, with an extension of
them by George J. Singer and Andrew Crosse.
These allude to many investigations made during previous years by
M. De Nelis, who reported upon them to Mr. Tilloch and to M. de la
Méthérie, and which show “very remarkable and permanent evidence of the
expansive power of the electric charge.” Singer adds: “It is difficult
to contemplate such extraordinary mechanical effects without admitting
that the power by which they are produced has at least the leading
characteristics of a material substance.” At p. 127, Vol. XLVIII of the
_Phil. Mag._, is an account of some further electrical experiments
of M. De Nelis, one of which is intended to improve the simple current
with an apparatus not insulated by discs. In this communication, which
bears date July 10, 1815, he discourses upon the theory of the two
fluids.
=A.D. 1816.=--Coxe (John Redman), M.D., Professor of Chemistry in
the University of Pennsylvania, is the second to propose a system of
transmitting signals, based, like Sömmering’s (A.D. 1809),
upon the discovery of Nicholson and Carlisle.
In the first series of Dr. Thos. Thomson’s _Annals of Philosophy_
for 1816 (not 1810), Vol. VII. pp. 162, 163, will be found Coxe’s
letter “On the Use of Galvanism as a Telegraph,” wherein he says:
“I have contemplated this important agent as a probable means of
establishing telegraphic communication with as much rapidity, and
perhaps less expense, than any hitherto employed. I do not know how far
experiment has determined galvanic action to be communicated by means
of wires; but there is no reason to suppose it confined as to limits,
certainly not as to time. Now, by means of apparatus fixed at certain
distances, as telegraphic stations, by tubes for the decomposition
of water, metallic salts, etc., regularly arranged, such a key might
be adopted as would be requisite to communicate words, sentences or
figures, from one station to another, and so on to the end of the
line.... As it takes up little room, and may be fixed in private, it
might in many cases of besieged towns, etc., convey useful intelligence
with scarcely a chance of detection by the enemy. However fanciful in
speculation, I have no doubt that, sooner or later, it will be rendered
in useful practice. I have thus, my dear sir, ventured to encroach
on your time with some crude ideas that may serve perhaps to elicit
some useful experiments in the hands of others. When we consider what
wonderful results have arisen from the first trifling experiments
of the junction of a small piece of silver and zinc in so short a
period, what may not be expected from the further extension of galvanic
electricity? I have no doubt of its being the chief agent in the hands
of nature in the mighty changes that occur around us. If metals are
compound bodies, which I doubt not, will not this active principle
combine their constituents in numerous places so as to explain their
metallic formation; and if such constituents are in themselves
aeriform, may not galvanism reasonably tend to explain the existence of
metals in situations in which their specific gravities certainly do not
entitle us to look for them?”
Coxe does not appear, however, to have at any time made satisfactory
experiments, and his systems were considered impracticable until worked
out by Alex. Bain during the year 1840.
At pp. 99–110, Vol. II of Dr. Coxe’s _Emporium of Arts and Sciences_,
Philadelphia, 1812, will be found his illustrated “Description of a
Revolving Telegraph,” for conveying intelligence by figures, letters,
words or sentences, upon which plan, he says, he constructed a small
telegraph that worked “readily and appropriately, although by no means
fitted with the various pulleys, etc., to facilitate the motion of the
ropes.”
REFERENCES.--For full explanation of Coxe’s systems, see L.
Turnbull, “Elect. Mag. Tel.” Highton’s “Electric Telegraph,” p.
39; _Jour. Franklin Inst._, Vol. XXI. for 1851, pp. 332, 333;
_Comptes Rendus_ for 1838, Vol. VII. pp. 593, etc.; _Sci. Am.
Supp._, Nos. 404, p. 6446, and 453, p. 7234; Alfred Vail, “The
American Electro-Magnetic Telegraph,” pp. 128, 129; Prime’s
“Life of Morse,” p. 263.
=A.D. 1816.=--In Part I of the _Philosophical Transactions_ for 1816,
and at p. 14, Vol. XLVII of the _Philosophical Magazine_, will be seen
an account of the observations and experiments made by Mr. John T.
Todd on the _torpedo_ off the Cape of Good Hope, during the year 1812
(“Abstracts of Papers ... Roy. Soc.,” Vol. II. p. 57).
It is said that the _torpedo_ in this locality is never more than
eight nor less than five inches in length, and never more than five
nor less than three and a half inches in breadth. Mr. Todd found the
columns of their electrical organs to be larger and less numerous in
proportion than those described by Hunter, and that they appeared to
be of a cylindrical form, while from a number of experiments he drew,
among other conclusions, the fact that a more intimate relation exists
between the nervous system and electrical organs of the _torpedo_,
both as to structure and functions, than between the same and
whatsoever organs of any known animal. (See Hunter at A.D.
1773.)
Reports of another series of experiments, carried on by Mr. Todd at
La Rochelle during 1816, will be found in the _Phil. Trans._ for
the year following as well as at p. 57, Vol. II of the “Abstracts of
Papers ... of the _Phil. Trans._, 1800–1830.” The last-named
investigations were made especially to determine whether the
_torpedo_ possessed any voluntary power over the electrical
organs, either in exciting or interrupting their action, except
through the nerves of these organs.
=A.D. 1816.=--Philip--Phillip--(Wilson), English physician,
publishes in the _Philosophical Transactions_ a continuation of
researches made by him to establish the relations existing between
the phenomena of life and voltaic electricity. Noad gives (“Manual,”
pp. 341–344) an account of some of the experiments made on animals to
prove the analogy existing between the galvanic energy and the nervous
influence, and he alludes also to the fact of asthma having been
relieved by galvanism through Dr. Philip, whose treatment had received
the endorsement of Dr. Clarke Abel, of Brighton.
REFERENCES.--_Journal of Science_, Vol. IX. See also Faraday’s
“Experimental Researches,” 1791 and note; “Abstract of Papers
... _Phil. Trans._, 1800–1830,” Vol. II for 1822, p. 156.
=A.D. 1816.=--The Rev. James Bremmer, of the Shetland Islands, is
rewarded by the Society of Arts for his night telegraph, the operation
of which consists in the alternate exhibition and concealment of a
torch in manner similar to that devised by Joachimus Fortius for
Bishop Wilkins, as stated at A.D. 1641. This plan is said to have been
successfully operated between the Copeland Island lighthouse and Port
Patrick on the other side of the English Channel.
Particulars of the above-named night telegraph, as well as of the
apparatus devised for day service, will be found in the _Trans. of
the Soc. of Arts_, Vol. XXXIV. pp. 30, 213–227. The day telegraph
consisted of a framework, having two circular openings, in each of
which was a semicircular screen or shutter which, revolving upon
an axis in the centre of the circle, was capable of assuming four
different positions. This contrivance expressed an alphabet of sixteen
letters, by dividing the latter into four classes of four each, and
making one screen or shutter express the class, while the other
indicated the number of the letter in that class.
=A.D. 1816.=--Sir Home Riggs Popham (1762–1820) British naval
officer, who had been a rear-admiral in 1814, introduces his land
semaphore which shows a great improvement upon all previous ones and
at once replaces the Murray apparatus heretofore used by the English
Admiralty (see A.D. 1795). It consists only of two arms placed
upon the same hollow hexagonal mast, and movable upon separate pivots,
each of which can be made to assume six different positions, giving
together forty-eight different signals. It is fully described and
illustrated at pp. 30, 167–177, Vol. XXXIV of the _Trans. of the Soc.
of Arts_, and also appears in the “Telegraph” article, Vol. II of
the “Encycl. of Useful Arts,” as well as at p. 149, Vol. XXIV of the
“Penny Encycl.,” at pp. 67, 68, Vol. VIII of the (“Arts and Sciences”)
“English Encycl.,” and in the “Telegraph” article by Sir John Barrow,
one of the secretaries to the Admiralty, in the seventh “Britannica.”
In this same year (1816), Sir Home Popham also introduced a ship
semaphore, which latter, as well as other similar devices of his
construction, is to be found in the several publications already
mentioned (the “Navy” article of the “Britannica” and pp. xii, xiii of
Ronalds’ “Catalogue”).
=A.D. 1816.=--Ronalds (Francis), English experimentalist
(1788–1873)--F.R.S., 1844, knighted 1870--whose serious attention
to the development of electrical science appears to date from his
meeting with M. De Luc in 1814, constructs at Hammersmith his telegraph
which is the type of all dial instruments and which first presents
the employment of two synchronous movements at the two stations. The
telegraph is fully described and illustrated in the “Description of an
Electrical Telegraph and of Some Other Electrical Apparatus,” 8vo, 83
pages, which Mr. Ronalds issued in pamphlet form, London, 1823, and
which is said to be the first work published on electric telegraphy.
Copious extracts from this are to be found at pp. viii-xi of the
Ronalds “Catalogue,” and at pp. 129, 135–145, of Fahie’s “History,” the
latter also containing several fine plates reproduced from the original
work.
For his experimental line, Ronalds “erected two strong frames of wood
at a distance of 20 yards from each other, and each containing 19
horizontal bars; to each bar he attached 37 hooks, and to the hooks
were applied as many silken cords, which supported a small iron wire
(by these means well insulated), which (making its inflections at the
points of support) composed in one continuous length a distance of
rather more than eight miles.” After making many experiments with this
overhead line, he thus laid one underground:
“A trench was dug in the garden 525 feet in length, and four feet deep.
In this was laid a trough of wood two inches square, well lined on the
inside and out with pitch, and within this trough thick glass tubes
were placed, through which the wire ran.”
His biographer, Mr. Frost, adds:
“In order to prevent the tubes from breaking by the variation of
temperature, each length was laid a short distance from the next
length, and the joint made with soft wax. The trough was then covered
with pieces of wood, screwed upon it whilst the pitch was hot. They
were also well covered with pitch, and the earth then thrown into the
trench again.”
Mr. Edward Highton, at p. 40 of his work, the “Electric Telegraph,”
1852, says:
“Ronalds employed an ordinary electric machine and the pith-ball
electrometer in the following manner. He placed two clocks at two
stations; these two clocks had upon the second hand arbor a dial with
twenty letters on it; a screen was placed in front of each of these
dials, and an orifice was cut in each screen, so that only one letter
at a time could be seen on the revolving dial. The clocks were made to
go isochronously; and as the dials moved round the same letter always
appeared through the orifices of each of these screens. The pith-ball
electrometers were hung in front of the dials. The attention of the
observer was called through the agency of an inflammable air gun fired
by an electric spark.”
Realizing the value of his invention, Ronalds strove to bring it before
the English Government, but was met (Aug. 5, 1816), with much the same
encouragement we have seen vouchsafed Sharpe (A.D. 1813), and Wedgwood
(A.D. 1814), viz. “Telegraphs of any kind are now wholly unnecessary
and no other than the one now in use will be adopted.” The one alluded
to was the semaphore line between London and Portsmouth, originally
of the Chappe pattern and improved upon by Charles W. Pasley and Rear
Admiral Popham.
Alluding to Mr. (afterward Sir) John Barrow’s letter in a note at p. 24
of his work Ronalds says:
“... Should they again become necessary, however, perhaps electricity
and electricians may be indulged by his Lordship and Mr. Barrow with an
opportunity of proving what they are capable of in this way.”
He was so disappointed that he not long after announced his “taking
leave of a science which once afforded him a favourite source of
amusement,” and that he was “compelled to bid a cordial adieu to
electricity.” Fortunately for the scientific world, however, he
afterward gave his attention again to electrical matters as is
evidenced by many important papers contained in the publications noted
below.
In Ronalds’ afore-named work the phenomenon of retardation of signals
in buried wires is clearly foreseen and described, although Zetzsche
endeavours to combat this assertion at p. 38 of his “Geschichte der
Elektrischen Telegraphie,” Berlin, 1867. Speaking of the apprehended
difficulty of keeping the wire charged with electricity, Ronalds
suggests that when not at work “the machine be still kept in gentle
motion to supply the loss of electricity by default of insulation;
which default, perhaps, could not be avoided, because (be the
atmosphere ever so dry, and the glass insulators ever so perfect),
conductors are, I believe, robbed of their electricity by the same
three processes by which Sir Humphry Davy and Mr. Leslie say that
bodies are robbed of their sensible heat, viz. by radiation, by
conduction, and by the motion of the particles of air.” He also gives
descriptions of an improved electrical machine (eighth “Britannica,”
Vol. VIII. p. 536; _Sci. Am. Supp._, No. 647, p. 10326; Noad’s
“Manual,” p. 69), of a new method of electrical insulation and of some
experiments on Vesuvius (_Quarterly Jour. of Sci._, Vols. II.
p. 249; XIV. pp. 332–334), of a new electrograph for registering the
charge of atmospheric electricity, of a pendulum doubler (_Edin.
Phil. Jour._, Vol. IX, 1823, pp. 323–325) and of an attempt to apply
M. De Luc’s electric column to the measurement of time. His other
contributions relative to the dry pile are to be found in the _Phil.
Mag._, Vols. XLIII. p. 414, and XLV. p. 466.
REFERENCES.--“Biog. Mem. of Sir Francis Ronalds, F.R.S.,” by
Alfred J. Frost, in Ronalds’ “Catalogue”; “Mem. of Dist. Men of
Science,” by William Walker; Ronalds’ “Corres. and Memoir.,”
in 1848–1849, to 1853, to April 17, 1855, to June 5, 1856, to
Sept. 2, 1862, and in 1866–1870; Ronalds’ “Walk Through ... Exh.
of 1855”; _Illustrated London News_ of April 30, 1870; eighth
“Britannica,” Vol. VIII. pp. 622, 627, for Ronalds’ improved
electrometers and his telegraph; _Nature_, London, Nov. 23,
1871, Vol. V. p. 59; _Journal of the Telegraph_, March 15,
1875, Vol. VIII. p. 82, reporting the inaugural address of Mr.
Latimer Clark before the English Society of Tel. Engineers;
_Comptes Rendus_ for 1838, Vol. VII. pp. 593, etc.; _Sci. Am.
Supp._, No. 384, pp. 6, 127; No. 547, p. 8735, and No. 659,
p. 10521, for his Telegraph; “Bombay Mag. Observatory,” 1850;
_Fortschrift des Phys._, Vol. III. p. 586, and Buys-Ballot
“Meteor. Preisfrage,” 1847, for Ronalds’ apparatus to measure
atmospheric electricity; _Phil. Mag._, Vols. XLIV. p. 442;
XLV. p. 261; XLVI. p. 203; and third series, Vols. XXVIII for
1846; XXXI. p. 191; British Ass. Reports for 1845, 1846, and
Reports concerning the Kew Observatory for 1845, 1850, 1852;
_Phil. Trans._ for 1847, Moigno’s _Le Cosmos_, Vol. XIII; L. Von
Forster, “All. Bauzeitung” for 1848, p. 238; Noad’s “Manual,”
pp. 184, 185, 748; Knight’s “Mechanical Dictionary,” Vol. I. p.
708; Turnbull’s “Electro-magnetic Telegraph,” p. 22; _Annals
of Electricity_, Vol. III. p. 449; “English Cyclop.” (Arts and
Sci.), Vol. VIII. pp. 71, 72; _Jour. Soc. Teleg. Eng._, 1879,
Part XV, xxxviii; Vol. VIII, first part, p. 361; Reply to Mr. W.
F. Cooke’s pamphlet, “The Elec. Teleg.: Was it Invented by Prof.
Wheatstone?” London, 1855; Du Moncel, Vol. III; “Telegraphic
Tales,” 1880, p. 42; J. D. Reid, “The Telegraph in America,”
1887, p. 71; Ure’s “Dict. of Arts,” etc., London, 1878, Vol. II
(Elect. Metal.), p. 230; T. P. Schaffner, “Tel. Man.,” 1859, pp.
147–156; Silliman, “Principles of Physics,” 1869, p. 617; “Edin.
Phil. Journal,” 1823, Vol. IX. pp. 322, 395.
=A.D. 1816.=--Porret (Robert) (1783–1868) communicates to the _Annals
of Philosophy_ (Vol. VIII. p. 74) a paper “On Two Curious Galvanic
Experiments” (Electrovection, Voltaic Endosmose, or Electro-chemical
Filtration).
He observed that when water was placed in a diaphragm apparatus, one
side of which was connected with the positive and the other side with
the negative electrode of the battery, that a considerable portion
of the liquid was transferred from the positive toward the negative
side of the arrangement. It has since been found that the same result
occurs in a minor degree when saline solutions are electrolyzed,
and, generally, the greater the resistance which the liquid offers
to electrolysis the greater is the amount which is thus mechanically
carried over.... It appears from the researches of Wiedemann (Pogg.,
_Ann._, Vol. LXXXVII. p. 321), which have been confirmed by those of
Quincke, that the amount of liquid transferred, _cæteris paribus_,
is proportioned to the strength or intensity of the current; that it
is independent of the thickness of the diaphragm by which the two
portions of liquid are separated; and that when different solutions
are employed, the amount transferred in each case, by currents of
equal intensity, is directly proportional to the specific resistance
of the liquid. Miller, from whom the above is taken, says that this
transfer has been minutely studied by Quincke, and gives an account of
the latter’s work extracted from the _Ann. de Chimie_, LXIII. p. 479.
Brewster’s allusion to Porret and Wiedemann (eighth “Britannica,” Vol.
VIII. p. 630) is followed by the statement that Mr. Graham considers
ordinary endosmose as produced by the electricity of chemical action.
REFERENCES.--Graham, Vol. II. p. 266; De la Rive’s
“Electricity,” Chap. IV. pp. 424–443; “Roy. Soc. Cat. of Sci.
Papers,” Vol. IV. pp. 987, 988; Wm. Henry, “Elem. of Exp. Chem.”
1823, Vol. I. p. 178; C. Matteucci, “Traité des Phénom. Elect.
Phys.,” 1844, p. 262 for Porret and Becquerel; Sturgeon’s “Sc.
Researches,” Bury, 1850, p. 544; Poggendorff, Vol. II. p. 503;
“Bibl. Britan.,” Vol. III, N.S., 1816, p. 15 (Thomson’s “Annals”
for July 1816).
=A.D. 1817.=--Mr. J. Connolly makes known through an English
and French pamphlet, entitled “An Essay on Universal Telegraphic
Communication,” the details of his portable telegraph.
As shown in the thirty-sixth volume of the _Transactions of the
Society of Arts_ and in the twenty-fourth volume of the “Penny
Cyclopædia,” his apparatus consists merely of three square boards
painted with simple devices, like triangles, crescents, etc., the
colours on the one side being the reverse of those on the other. Each
of the six figures thus obtained is capable of producing four different
distinct signals, making in all twenty-four, by successively turning
each side of the board downward. In experiments made at Chatham, boards
only eighteen inches square were found to answer for a distance of two
miles, with a telescope having a magnifying power of twenty-five; and
Mr. Connolly had also, it is said, exhibited these signals between
Gros-nez and Sarque, a distance of seventeen miles, with boards twelve
feet square.
At pp. 205, 208, of the _Transactions of the Society of Arts_,
1818, Vol. XXXV, and at p. 98, Vol. XXXVI for 1819, will be found
Mr. Connolly’s system of telegraphing by means of flags in manner
different from that of Lieut.-Col. John Macdonald alluded to at Pasley,
A.D. 1808.
=A.D. 1817.=--In the “Encycl. Brit.” article treating of the influence
of magnetism on chemical action, it is said that M. Muschman, Professor
of Chemistry in the University of Christiania, made experiments to
ascertain the effect of the earth’s magnetism on the precipitation of
silver.
Desirous of explaining the chemical theory of the tree of Diana
(_Arbor Dianæ_, first observed by Leméry), “he took a tube like a
siphon and poured mercury into it, which accordingly occupied the lower
part of the two branches; above the mercury he poured a strong solution
of nitrate of silver. He then placed the two branches of the siphon
so that the plane passing through them was in the magnetic meridian,
and after standing a few seconds the silver began to precipitate
itself with its natural lustre; but it accumulated particularly in the
northern branch of the siphon, while that which was less copiously
precipitated in the other branch had a less brilliant lustre, and was
mixed with the mercurial salt deposited from the solution.” Muschman
and Prof. Hansteen, having repeated this experiment with the same
result, concluded that the magnetism of the earth had an influence
on the precipitation of silver from a solution of its nitrate, and
Muschman inferred from the experiment the identity of galvanism and
magnetism (eighth “Britannica,” Vol. XIV. p. 42).
=A.D. 1817.=--Freycinet (Claude Louis Desaulses de) (1779–1842),
captain in the French navy, is sent in command of an expedition fitted
out by the French Government for the purpose of making scientific
observations in a voyage round the world. The experimental stations
were the Island of Rawak (near the coast of Guinea), Guam (one of the
Ladrones), the Isle of France, Mowi (one of the Sandwich Islands),
Rio Janeiro, Port Jackson, Cape of Good Hope, Paris and the Falkland
Islands, as described in his “Voyage Autour du Monde ...” Paris, 1842.
His observations on the diurnal variations of the needle, which confirm
the investigations made by Lieut.-Col. John Macdonald (A.D.
1808), are to be found at p. 54, Vol. XIV of the eighth “Britannica.”
REFERENCES.--His “Voyage de Découvertes ... 1800–1804 ...” (F.
Péron and Louis Freycinet), also his “Navigation et Géog. ...”
1815; the note at p. 158, Vol. I of Humboldt’s “Cosmos,” London,
1849; _Phil. Mag._, Vol. LVII. p. 20.
=A.D. 1817.=--In Vol. XLII. pp. 165, 166, of the _Transactions
of the Society of Arts_ will be found a record of the explanation
of his magnetic guard for needle pointers which Mr. Westcott made
before the Committee of Mechanics during the year 1817. This is said to
consist of several “bar magnets smeared over with oil placed in a frame
behind the grindstone.”
=A.D. 1818.=--Bostock (John) (1774–1846), English physician, F.R.S.,
lecturer at Guy’s Hospital, publishes in London his “Account of the
History and Present State of Galvanism,” which is scarcely more than a
compilation of works treating of that branch of science.
One of the passages is, however, worth quoting, for it reflects the
opinion shared by many physicists of the time that the resources of
the galvanic field were already wellnigh exhausted. It thus appears
at p. 102: “Although it may be somewhat hazardous to form predictions
respecting the progress of science, I may remark that the impulse which
was given in the first instance by Galvani’s original experiments,
was revived by Volta’s discovery of the pile, and was carried to
the highest pitch by Sir H. Davy’s application of it to chemical
decomposition, seems to have, in a great measure, subsided. It may be
conjectured that we have carried the power of the instrument to the
utmost extent of which it admits; and it does not appear that we are at
present in the way of making any important additions to our knowledge
of its effects, or of obtaining any new light upon the theory of its
action.”
Bostock is also the author of “Outline of the History of the Galvanic
Apparatus”; “On the Theory of Galvanism” (_Nicholson’s Journal_ for
1802); “On the Hypothesis of Galvanism” (_Annals of Philosophy_, III,
1814), and of other works upon different scientific subjects. Reference
is made by Mr. William Leithead (“Electricity,” London, 1837, Chap. VI.
pp. 296, 297) to Bostock’s “Elementary System of Physiology,” 1827,
Vol. II. pp. 413, etc., wherein is shown among other results, that,
contrary to the views of Dr. Philip, there is no necessary connection
between “the nervous influence” and the action of the glands. At p. 306
of Leithead appears another extract, from the third volume of Bostock,
relative to the application of the electro-physiological theory in
elucidating the phenomena of disease.
REFERENCES.--Poggendorff, Vol. I. pp. 249, 250; “Nicholson’s
Journal,” Vols. II. p. 296, and III. p. 3; Figuier, “Expos. et
Histoire,” 1857, Vol. IV. p. 425; Gilbert, Vol. XII. p. 476.
=A.D. 1819.=--Hansteen (Christoph) (1784–1873), Norwegian astronomer
and physicist, embodies in his notable work, “Untersuchungen über den
Magnetismus der Erde ...” (“Inquiries regarding the magnetism of the
earth”), the result of his extensive researches concerning terrestrial
magnetism, the account of which is accompanied by a chart indicating
the magnetic direction and dip at numerous places. This work, which is
said to have been practically completed in 1813 (Humboldt, “Cosmos,”
1859, Vol. V. p. 66), was translated by the celebrated Peter Andreas
Hansen (Poggendorff, Vol. I. pp. 1013–1015) from the original
manuscript and published in German. It attracted much attention
throughout the scientific world, and so highly was it thought of that
in almost all the voyages of discovery afterwards undertaken most
magnetic observations were made according to its directions.
Through the “Encyclopædia Britannica” we learn that Hansteen’s able
work was first made known in England by Sir David Brewster through
two articles in the _Edin. Phil. Journal_ for 1820, Vol. III. p.
138, and Vol. IV. p. 114, and that an account of his subsequent
researches, drawn up by Hansteen himself, appeared in the _Edin.
Journal of Science_ for 1826, Vol. V. p. 65. It is also stated that
the Royal Society of Denmark proposed in 1811 the prize question,
“Is the supposition of one magnetical axis sufficient to account for
the magnetical phenomena of the earth, or are two necessary?” Prof.
Hansteen’s attention had been previously drawn to this subject by
seeing a terrestrial globe, on which was drawn an elliptical line
round the south pole and marked _Regio polaris magnetica_, one of the
foci being called _Regio fortior_, and the other _Regio debilior_. As
this figure professed to be drawn by Wilcke, from the observations of
Cooke and Furneaux, Hansteen was led to compare it with the facts; and
the result of his researches was favourable to that part of Halley’s
theory which assumes the existence of four poles and two magnetic axes.
Hansteen’s Memoir, which was crowned by the Danish Society, forms
the groundwork of his larger volume published in 1819. “In his fifth
chapter, on the Mathematical Theory of the Magnet, he deduces the law
of magnetic action from a series of experiments similar to those of
Hauksbee and Lambert.... In determining the intensity of terrestrial
magnetism Professor Hansteen observed that the time of vibration of
a horizontal needle varied during the day. Graham had previously
suspected a change of this kind, but his methods were not accurate
enough to prove it. Hansteen found that the minimum intensity took
place between ten and eleven a.m., and the maximum between four and
five p.m. He concluded also that there was an annual variation, the
intensity being considerably greater in winter near the perihelion, and
in summer near the aphelion; that the greatest monthly variation was a
maximum when the earth is in its perihelion or aphelion, and a minimum
near the equinoxes; and that the greatest daily variation is least in
winter and greatest in summer. He found also that the aurora borealis
weakened the magnetic force, and that the magnetic intensity is always
weakest when the moon crosses the equator.”
According to Dr. Whewell (“History of Induc. Sciences,” 1859, Vol. II.
p. 226), the conclusions reached by Hansteen respecting the position
of the four magnetic “poles” excited so much interest in his own
country that the Norwegian Storthing, or Parliament, by a unanimous
vote provided funds for a magnetic expedition which he was to conduct
along the north of Europe and Asia, and this they did at the very time
when, strange to say, they refused to make a grant to the King for
building a palace at Christiania. The expedition was made in 1828–1830,
and verified Hansteen’s anticipations as to the existence of a region
of magnetic convergence in Siberia, which he considered as indicating
a “pole” to the north of that country. The results were published in
Hansteen and Due’s “Resultate magnetischer ...” (“Magn., Astron. and
Méteor. Obs. on Journey through Siberia”) which appeared in 1863.
In the Sixth Dissertation, Chap. VII of the “Encycl. Brit.,” it is
said that, next to Prof. Hansteen, science is mainly indebted for
the great extension of our knowledge of the facts and the laws of
terrestrial magnetism to two illustrious German philosophers, Baron
Alexander von Humboldt and Prof. Karl Friedrich Gauss (1777–1855). An
account is therein given of Gauss’s individual investigations, as well
as of the researches he made in conjunction with Wilhelm Eduard Weber
(1804–1891), who was likewise a professor at Göttingen. Of Alex. von
Humboldt, we have spoken fully under date 1799, and of Gauss and Weber,
mention has already been made at Schilling (A.D. 1812).
The very valuable contributions of Gauss and Weber appear throughout
all the many scientific publications of the period, notably in the
“Abhandlung d. Gött. Geselsch. d. Wiss.,” their joint work being shown
to advantage in the important “Resultate ... des Magnet. Vereins,”
published in Leipzig, 1837–1843.[58]
REFERENCES.--For M. Hansteen’s scientific papers and for an
account of additional magnetic results obtained by himself and
others, consult the eighth “Britannica,” Vols. I. p. 745; IV.
p. 249; XIV. pp. 15, 23, 42 (experiment with M. Muschman), 50,
55, 57–64, _et seq._, for Morlet and others; Thomson’s “Outline
of the Sciences,” London, 1830, pp. 546–548; Whewell, “History
of the Induc. Sci.,” Vol. II. pp. 613, 615, also p. 219 for
Yates and Hansteen; Johnson’s new “Univer. Encycl.,” 1878, Vol.
III. pp. 231–234 for Morlet, etc.: Weld’s “Hist. of Roy. Soc.,”
Vol. II. p. 435; “Edin. Jour. of Sci.,” London, 1826, Vols. I.
pp. 87, 334; V. pp. 65–71, 218–222; “Report of Seventh Meeting
British Association,” London, 1838, Vol. VI. pp. 76, 82; J.
G. Steinhauser’s articles published between 1803 and 1821;
Harris’ “Rudimentary Magnetism,” London, 1852, Part. III. pp.
38, 39, 111; _Phil. Mag._, Vol. LIX. p. 248, and _Phil. Mag._
or _Annals_, Vol. II. p. 334; “Zeitschr. f. pop. Mitth.,” I. p.
33; Schweigger’s _Journal_, 1813–1827; Poggendorff’s _Annalen_,
1825–1855; “Académie Royale de Belgique” for 1853, 1855,
1865; C. Hansteen and C. Fearnley, “Die Univ.-Sternwarte ...”
1849; Hansteen, Lundh and Muschman, “Nyt. Mag. for Naturvid,”
1823–1856. See likewise his biography in the “English Cyclop.
Supplement,” pp. 642, 643; “Catal. Roy. Soc. Sc. Pap.,” Vol.
III. pp. 167–172; Vol. VI. p. 681, Vol. VII. p. 905; Houzeau
et Lancaster, “Bibl. Gén.,” Vol. II. p. 157; “Edin. Phil.
Journal,” 1823, Vol. IX. p. 243; “Annual Rec. Sc. Disc.,” 1873,
p. 683; 1875, p. 155; Knight’s “Amer. Mech. Dict.,” 1875, Vol.
II. p. 1374, and eighth “Britan.,” Vol. XIV. p. 49, regarding
Hansteen’s lines of no variation for 1787; Humboldt’s “Cosmos,”
1859, Vol. V. pp. 110–111, for the investigations of Hansteen,
Sir Ed. Belcher and others, those of the last named being
treated of at p. 493 of the _Phil. Trans._ for 1832; Noad,
“Manual,” pp. 529, 530, 534, 616, 617, etc.; Appleton’s “New Am.
Cycl.,” Vol. XI. p. 64.
=A.D. 1819.=--Hare (Robert) (1781–1858) who was for twenty-nine
years Professor of Chemistry in the Pennsylvania University, publishes
in Philadelphia “A New Theory of Galvanism, Supported by Some
Experiments and Observations Made by Means of the Calorimotor ...”
of which an English edition appears in London the same year. (A full
review of this work is to be found more particularly at p. 206, Vol.
LIV of the _Philosophical Magazine_; in the “Encycl. Metropol.,”
Vol. IV (Galvanism), p. 222; in Ure’s “Dictionary of Chemistry,” Am.
ed., article “Calorimotor”; at p. 187 of the _Phil. Trans._ for
1823; at pp. 409, 410, Vol. I of Gmelin’s “Chemistry,” and at pp.
413–423, Vol. I of Silliman’s _Am. Jour. of Sci._, the last named
being accompanied by a very fine illustration of the Calorimotor.)
This apparatus, which has already been alluded to (Pepys, A.D. 1802),
consists of sheets of zinc about 9 inches by 6, and of copper about 14
inches by 6, coiled around one another nearly half an inch apart; there
being in all 80 coils, 2½ inches in diameter, which are let down by
means of a lever into glass vessels containing the acid solution. Dr.
Hare observes:
“Volta considered all galvanic apparatus as consisting of one or more
electromotors, or movers of the electric fluid. To me it appeared
that they were movers of both heat and electricity; the ratio of the
quantity of the latter put in motion to the quantity of the former put
in motion being as the number of the series to the superficies. Hence
the word _electromotor_ can only be applicable when the caloric
becomes evanescent, and electricity almost the sole product, as in De
Luc’s and Zamboni’s columns; and the word _calorimotor_ ought to
be used when electricity becomes evanescent and caloric appears the
sole product.”
“It afterwards appeared quite natural,” remarks Mr. W. B. Taylor (Note
B, “Mem. of Jos. Henry,” p. 376) “to distinguish these classes of
effects by the old terms--‘intensity’ for electromotive force, and
‘quantity’ for calorimotive force. There is obviously a close analogy
between these differences of condition and resultant, and the more
strongly contrasted conditions of mechanical and chemical electricity;
and indeed the whole may be said to lie in a continuous series,
from the highest ‘intensity’ with minimum quantity, to the greatest
‘quantity’ with minimum intensity.”
Two years later (1821), Dr. Hare constructed his _galvanic
deflagrator_. It consists of two pairs of troughs, each ten feet
long, and containing 150 galvanic pairs, so arranged that the plates
can all be simultaneously immersed into or withdrawn from the acid.
Each pair turns on pivots made of iron, coated with brass or copper,
and a communication is established between these and the voltaic series
within by means of small strips of copper. The “Encycl. Brit.” gives
a full description of the construction and working of the apparatus,
as do also the “Encycl. Metropol.,” Vol. IV (Galv.), p. 176; Noad
(“Manual,” pp. 266, 267); Gmelin (“Chemistry,” Vol. I. pp. 409, 410),
and Silliman (“Journal of Sci. and Arts,” Vol. VII. p. 347). The
first-named publication says of Dr. Hare’s _deflagrator_:
“A brilliant light, equal to that of the sun, was produced between
charcoal points, and plumbago and charcoal were fused by Profs.
Silliman and Griscom. By a series of 250, baryta was deflagrated, and
a platina wire, three-sixteenths of an inch in thickness, ‘was made to
flow like water.’ In the experiments with charcoal, the charcoal on the
copper side had no appearance of fusion, but a crater-shaped cavity was
formed within it, indicating that the charcoal was volatilized at this
side and transferred to the other, where it was condensed and fused,
the piece of charcoal at this pile being elongated considerably. This
fused charcoal was four times denser than before fusion. In a letter
from Prof. Silliman, which was transcribed in the _Sc. Am. Sup._
for Sept. 21, 1878, he says: ‘Undoubtedly the earliest exhibitions
of electric light from the voltaic battery were those made with the
deflagrators of Dr. Hare by Prof. Silliman at New Haven in 1822, and
subsequently on a magnificent scale at Boston in 1834, when an arc of
over five inches diameter was produced by the simultaneous immersion
of 900 large-sized couples of Hare’s deflagrator. But no means had
then been devised for the regulation of the electric light to render
it constant, and although the writer as early as 1842 used this light
successfully to produce daguerreotypes, the progress of invention had
yet to make further use of the discovery of science before electrical
illumination was possible.’”
The description of Dr. Hare’s electrical machine (before alluded
to at Van Marum A.D. 1785), wherein the plate is mounted
horizontally so as to show both negative and positive electricity,
was published in London during 1823, and can be found in Vol. LXII of
the _Phil. Mag._, as well as at pp. 538, 604, 605, Vol. VIII of
the 1855 “Encycl. Brit.” In the last-named article mention is made of
the introduction of a band (illustrated Fig. 7, Plate CCXXII) which
prevents the plate from being cracked, as it frequently is, through
some hasty effort to put it in motion while it adheres to the cushions.
It is also therein stated that in order to offset the heavy expense
attending the breakage of large cylinders and plates, M. Walkiers
de St. Amand, of Brussels, among many others, made an apparatus
of varnished silk 25 feet long and 5 feet wide, capable of giving
sparks 15 inches long (see A.D. 1785), while Dr. Ingen-housz
constructed machines with pasteboard discs four feet in diameter,
soaked in copal or amber varnish dissolved in linseed oil, which gave
sparks of one and even two feet in length.
In the fifth volume, new series, of the _Amer. Phil. Trans._
will be found Dr. Hare’s “Description of an Electrical Machine,” with
a plate four feet in diameter, so constructed as to be above the
operator; also of a battery discharger employed therewith, and some
observations on the causes of the diversity in the length of the sparks
erroneously distinguished by the terms positive and negative. Hare is
also the inventor of a single gold-leaf electroscope of such great
delicacy that it has, he says, enabled him to detect the electricity
produced by one contact between a zinc and copper disc, each six
inches in diameter (Noad, “Manual,” p. 29; Harris’ “Rudim. Elect.,”
p. 50; Silliman’s _Journal_, Vol. XXXV). He invented several
other electrical appliances, and he is likewise the author of numerous
important memoirs which it would be impossible to detail in the narrow
limits of this “Bibliographical History.” They will, however, be found
recorded in the publications named below.
REFERENCES.--_Phil. Trans._ for 1769, Vol. LXIX. p. 659. See
also, for Walkiers de St. Amand, the entry at A.D. 1785, as
well as Lichtenberg’s _Magazin_, Vol. III, 1st, p. 118, for the
last-named year. To these might be added the machines made by
Mundt, of silken strips (Gren’s _Journal der Physik._, Vol. VII.
p. 319); by N. Rouland, “Descript. des mach, elec. à taffetas,”
Amsterdam, 1785; by Croissant and Thore; of paper by W. H.
Barlow (_Phil. Mag._, Vol. XXXVII. p. 428), of gutta percha;
as well as machines of rubber by Fabre and Kunneman, as shown
at Th. Du Moncel’s “Exposé des appl. de l’El.,” second ed., p.
399, and third ed., 1872, Vol. II. pp. 78, 122, 265, besides the
peculiarly constructed machines of Erdmann Wolfram (Ferussac,
“Bulletin des Sciences Tech.” for 1824); of G. H. Seiferheld,
“Beschreib ... elektrische mach,” 1787; of F. E. Neuman, as
modified by F. Zantedeschi (“Ann. Sci. Lom.-Ven.,” XII. p. 73),
and of those described at p. 420, Vol. II, and at p. 4, Vol.
III of _Nicholson’s Magazine_. Consult likewise, pp. 335, 340,
second Am. ed. of the “New Edin. Encycl.,” 1817. Poggendorff,
Vol. I. pp. 1018, 1019; “Cat. Sci. Papers of Roy. Soc.,” Vol.
III. pp. 177–182; Vol. VI. p. 182; Silliman’s _Am. Jour. Sci.
and Arts_, Vols. II. pp. 312, 326; III. p. 105; IV. p. 201; V.
p. 94; VII. pp. 103, 108, 351; VIII. pp. 99, 145; X. p. 67;
XII. p. 36; XIII. p. 322; XV. p. 271; XXIV. p. 253, XXV. p.
136; XXXI. p. 275; XXXII. pp. 272, 275–278, 280–285; XXXIII. p.
241; XXXV. p. 329; XXXVII. pp. 269, 383; XXXVIII. pp. 1, 336,
339; XXXIX. p. 108; XL. pp. 48, 303; XLI. p. 1, and XLIII. p.
291; _Phil. Mag._, Vols. LVII. p. 284; LXII. pp. 3, 8, etc.;
_Phil. Mag._ or _Annals_, Vol. VI. pp. 114, 171; _Journal of
the Franklin Institute_, third series. Vol. XV. pp. 188, etc.;
_Trans. of the Am. Phil. Soc._, N.S., Vol. VI. p. 297 (for Hare
and Allen) also pp. 339, 341, 343, and Vol. VII for 1841; “Mem.
Jos. Henry,” Washington, 1880, p. 82; Figuier, “Exp. et Hist.,”
1857, Vol. IV. pp. 391, 401, 402; Dr. Thomas Thomson, “Outline
of the Sc.,” London, 1830, pp. 515, 517; Appleton’s “New
Amer. Cycl.,” Vol. VII. p. 66; Appleton’s “Dict. of Machines,
Mechanics ...” 1861, pp. 432, 433; Dr. William Henry, “Elem. of
Exper. Chem.,” London, 1823, Vol. I. p. 169, and Supplement,
Chap. VII. p. 29; “Annual of Sc. Disc.” for 1862, p. 99.
=A.D. 1819.=--Gmelin (Leopold), the most distinguished member of
the family of that name, publishes, at Frankfort, 1817–1819, the first
edition of his celebrated “Handbuch d. theoret. Chemie,” which embodies
the whole extent of chemical science as it then existed and the fourth
and last edition of which, under the author’s supervision, appeared
during 1843–1845. This extensive work is well known, both in its
original form and through the very able translation of it made by Mr.
Henry Watts. In the report of the Council of the Chemical Society for
1854, it is said that “the greatest service which Gmelin rendered to
science--a service in which he surpassed all his predecessors and all
his contemporaries--consists in this: that he collected and arranged
in order all the facts that have been discovered in connection with
chemistry. His Handbuch der theoret Chemie stands alone. Other writers
on chemistry have indeed arranged large quantities of materials in
systematic order, but for completeness and fidelity of collation and
consecutiveness of arrangement, Gmelin’s Handbuch is unrivalled.”
Although many references have been made herein to Leopold Gmelin’s
treatment of such departments of science as directly appeal to the
readers of this compilation, it is well to mention some of the
headings under which they are to be found. They are, “Electricity,”
“Electro-chemical Theories,” “Electrolysis,” “Technical Apparatus of
Electricity,” “Theory of Galvanism,” “Galvanic Batteries,” “Magnetic
Condition of All Matter,” etc., etc., the whole occupying pp. 304 to
519, Vol. I of Gmelin’s English edition. The list of many of Leopold
Gmelin’s valuable contributions to science is given in the “Catalogue
Sc. Papers Roy. Soc.,” besides which may be mentioned his “Uber e
angebl. meteorische masse” (Gilbert, _Annalen_, LXXIII for 1823),
and his “Versuch einer elektro-chemisch. theorie” (Poggendorff’s
_Annalen der Physik und Chemie_, Vol. XLIV for 1838, while at pp.
547–550 of Mr. J. J. Griffin’s able work, published in London during
1858, will be found the results obtained by Prof. G. Magnus and by
Prof. Faraday with a summary of Gmelin’s conclusions under the heading
of “The Evidence of Electrolysis in Favour of the Radical Theory.”
GMELIN FAMILY
This family, which, through four generations, has been continuously
distinguished for its valuable contributions to chemistry as well as to
the natural and medical sciences, deserves equally well here of such a
special mention as was accorded to the Bernoulli and Cassini families,
under dates A.D. 1700 and 1782–1791.
Johann Georg Gmelin (1674–1728), a very able chemist and pharmaceutist
of Tübingen, was the father of:
Johann Conrad Gmelin (1707–1759), physician and author in the
same city of Tübingen.
Johann Georg Gmelin (1709–1755), distinguished naturalist and
chemist, who graduated as M.D. in his nineteenth year, became
a member of the St. Petersburg Acad. of Sc. and was sent by
the Empress Anna, in company with G. A. Müller and other noted
scientists, upon a ten years’ exploring expedition through
Siberia. He was one of the first explorers of Northern Asia, and
a genus of Asiatic plants was named Gmelina after him by Linnæus.
Philip Friedrich Gmelin (1722–1768), Professor of Botany and of
Chemistry at Tübingen, author of many scientific monographs.
Samuel Gottlieb Gmelin (1744–1774), elder son of Philip Friedrich,
who, like his uncle, graduated M.D. at nineteen and was sent two
years later by the Empress Catherine II upon a scientific tour through
South-Eastern Russia, is the author of “Historia Fucorum ...” as well
as of other contributions which were edited through the famous Pallas.
His biographical notice appears in the last volume of the “Reise durch
Russland ...” published at St. Petersburg.
Johann Friedrich Gmelin (1748–1804), M.D., succeeded his father,
Philip Friedrich, in the chair of chemistry and botany at the Tübingen
University, became Professor of Medicine at Göttingen in 1778 and a
member of “l’Académie des Curieux de la Nature.” He is the author
of the thirteenth edition of Linnæus’ “Systema Naturæ,” which,
notwithstanding Cuvier’s severe criticism of it, is said to be the
only work which even professes to embrace all the objects of natural
history described up to the year 1790 (“Encycl. Brit.,” 1855, Vol. IX.
p. 4). He is also the author of “Geschichte der Chemie ...” Göttingen,
1797–1799, and of “Prælectio de col. metal. a Volta ...” (“Commentat.
Soc. Gött.” XV (Phys.) for 1800–1803, p. 38). (See J. C. Poggendorff,
“Biogr.-Literar. Handwörterbuch,” Vol. I. pp. 914–915.)
His son, Leopold Gmelin (1788–1853), who has already been noticed,
practised chemical manipulation in the Tübingen pharmaceutical
laboratory of Dr. Christian Gmelin, the son of Johann Conrad, and
studied at Göttingen, Vienna and in Italy, after which he became
medical and chemical professor at Heidelberg, 1817–1851 (Poggendorff,
Vol. I. pp. 915–916).
Ferdinand Gottlob von Gmelin (1782–1848), elder son of Dr. Christian
Gmelin, was Professor of Medicine and of Natural History in the
Tübingen University, and wrote “Diss. sistens obs. phys. et chem. de
electricitate et galvanismo” during 1802 (Poggendorff, Vol. I. pp.
916–917).
Christian Gottlob Gmelin (1792–1860), brother of the last named, M.D.,
was Professor of Chemistry and Pharmacy at the Tübingen University, and
the author of “Experimenta electricitatem ...” 1820; “Uber d. Coagulat.
... d. Electricität” (Schweigger’s “Journal,” Vols. XXXVI for 1822);
“Analyse d. turmalins ...” (Schweigger’s “Journal,” Vols. XXXI for 1821
and XXXVIII for 1823--Poggendorff’s “Annalen,” Vol. IX for 1827), as
well as of a “Handbuch der Chemie,” published 1858–1861 (Poggendorff,
Vol. I. p. 917; _Phil. Mag._ or _Annals_, Vol. III. p. 460).
REFERENCES.--Gmelin and Schaub, “Effets Chimiques de la col.
metal ...” (“Magas. Encyclop.,” Vol. VI. p. 201); Eberhard
Gmelin’s letter to M. Privy Councillor Hoffmann of Mayence
(1787), and his new investigations (1789) on the subject of
animal magnetism (“Salzb. Med. Chir. Zeit.,” 1790, I. p. 358);
Whewell, “Hist. of the Ind. Sc.,” 1859, Vol. II. p. 348.
=A.D. 1819.=--Dana (J. F.), M.D. (1793–1827), Chemical Assistant
in Harvard University and Lecturer on Chemistry and Pharmacy in
Dartmouth College, writes, Jan. 25, 1819, to Prof. Benjamin Silliman
concerning his new form of portable electrical battery.
This apparatus, consisting of alternate plates of flat glass and of
tinfoil, the sheets of which latter are connected together, is fully
described at pp. 292–294, and is illustrated opposite p. 288, Vol. I
of Silliman’s _American Journal of Science_, 1818, wherein it is
stated that, while “in a battery of the common form, 2 feet long, 1
foot wide and 10 inches high, containing 18 coated jars, there will be
no more than 3500 square inches of coated surface,” a battery of Dana’s
construction will have no less than 8000 square inches covered with
tinfoil, allowing the sheet of glass and of foil to be a quarter of an
inch thick. In a brief description of this apparatus, which appears
at p. 468, Vol. V of Tilloch’s _Phil. Mag. and Journal_, it is
stated that a “battery constructed in this way contains, in the bulk of
a quarto volume, a very powerful instrument; and when made of glass it
is extremely easy, by varnishing the edges, to keep the whole of the
inner surfaces from the air, and to retain it in a constant state of
dry insulation.”
=A.D. 1820.=--Oersted--Örsted (Hans Christian), native of Denmark
(1770–1851), Professor of Natural Philosophy and founder of the
Polytechnic School in Copenhagen, makes known, through a small
four-page pamphlet entitled “Experimenta circa effectum conflictus
electrici in acum magneticam,” his great discovery of the intimate
relation existing between electricity and magnetism (Thomson’s _Annals
of Philosophy_ for October 1820, Vol. XVI, first series, pp. 273–276).
He thus lays the foundation of the science of electro-magnetism, which
subsequently was so materially developed by Ampère and Faraday.
It is said that after taking his doctor’s degree in 1799, he gave much
attention to galvanism, and that in the year 1800 he made important
discoveries as to the action of acids during the production of galvanic
electricity. He was one of the earliest to show the opposite conditions
of the poles of the galvanic battery, also that acids and alkalies are
produced in proportion as they neutralize each other. Upon his return
from a trip to France and Germany, 1801–3, he lectured on electricity
and the cognate sciences, publishing thereon a number of essays. (These
are to be found, more particularly, in J. H. Voigt’s _Magazin_, Vol.
III. p. 412; Van Mons’ _Journal_, No. IV. p. 68; the _Bulletin of the
Société Philomathique_, No. LXVII. an. xi. p. 128; A. F. Gehlen’s
_Neues Allgem. Journal d. Chemie_, Vols. III for 1804, VI for 1806,
VIII for 1808; Schweigger’s _Journal_, Vol. XX; _Phil. Mag._, Vol.
XXIII. p. 129; the “Skand. Lit.-Selskabs Skrifter,” Vol. I; “Oversigt
over det Kongl. ... Forhandlinger,” 1814–1815; “Nyt Biblioth. f.
Physik,” etc., Vol. IX, and in the _Journal de Physique_ as well as in
the _Journal du Galvanisme_.)
He revisited Germany during 1812, and, at the suggestion of Karsten
Niebuhr, published in Berlin his work “Ansicht der Chemischen
Naturgesetze. ...” (“Inquiry into the identity of chemical and electric
forces”), a translation of which was made by M. P. Marcel T. de Serres
under the title of “Recherches sur l’Identité. ...” (Fahie, “Hist. of
Electric Teleg.,” 1884, pp. 270–273). The last-named work appeared
at Paris during 1813, and not, as stated at p. 41, Vol. LVII of the
_Philosophical Magazine_, during 1807, which was the date of the
original small German edition.[59]
One of his biographers says that Oersted was lecturing one day to a
class of advanced students, when, as a means of testing the soundness
of the theory which he had long been meditating, it occurred to him
to place a magnetic needle under the influence of a wire uniting the
ends of a voltaic battery in a state of activity. “In galvanism,” said
he, “the force is more latent than in electricity, and, still more
so in magnetism than in galvanism; it is necessary therefore to try
whether electricity, in its latent state, will not affect the magnetic
needle.” He tried the experiment upon the spot and found that the
needle tended to turn at right angles to the wire, thus proving the
existence of electro-magnetism, or the relation of electricity and
magnetism as mutually productive of each other, and as evidences of a
common source of power. Previous to this time the identity of magnetism
and electricity had only been suspected. For several months Oersted
prosecuted experiments on the subject, and on the 21st of July 1820
promulgated his discovery through the Latin pamphlet above alluded to.
Therein he contends that there is always a magnetic circulation around
the electric conductor, and that the electric current in accordance
with a certain law always exercises determined and similar impressions
on the direction of the magnetic needle, even when it does not pass
through the needle but near it (the eighth edition of the “Encycl.
Britannica,” Fifth Dissertation, pp. 739, 740, 745; and the Sixth
Dissertation, pp. 973–976; Schaffner, “Tel. Manual,” 1859, Chap. VIII;
_Practical Mechanic_, Glasgow, 1842, Vol. III. p. 45).
For this discovery, which naturally excited the wonder of the entire
scientific world, he received the Copley medal of the English Royal
Society, the Dannebrog order of knighthood and numerous testimonials
from nearly every quarter of Europe. As observed by Mr. J. D. Forbes
(Sixth Disser. “Encycl. Brit.,” Vol. I), “the _desideratum_ of
a clear expression of the manifest alliance between electricity and
magnetism has been so long and so universally felt that the discovery
placed its author in the first rank of scientific men.... The prize of
the French Institute, which had been awarded to Davy for his galvanic
discoveries, was bestowed upon Oersted.”
Oersted’s experiments were repeated before the French Academy of
Sciences by M. De la Rive on Sept. 11, 1820, and, seven days later, as
we shall see, Ampère made known the law governing electro-magnetism
(Mme. Le Breton, “Hist. et. Appl. de l’Elect.,” Paris, 1884, pp.
72, 73; W. Sturgeon, “Sci. Researches,” Bury, 1850, p. 18; Higg’s
Translation of Fontaine’s “Electric Lighting,” London, 1878, p. 54).
The many investigations subsequently carried on by Oersted in different
branches of sciences are alluded to in the works named below. Perhaps
the most interesting, outside of the ones already spoken of, are those
attaching to thermo-electricity which he made in conjunction with Baron
Fourier, and independently of Dr. Seebeck.
REFERENCES.--Eighth “Britannica,” pp. 651 and 652, Vol. XXI, as
well as pp. 11 and 12, Vol. XIV of Oersted’s “Efterretning om
nogle nye, af Fourier og Oersted ...” Kiobenhaven, 1822–1823,
translated into French as mentioned in Vol. XXII of the _Annales
de Chimie et de Physique_; “Oversigt over det Kongl. ...” for
1822–1823 and 1823–1824; Poggendorff, Vol. III. pp. 309–312;
“Catal. Sci. Papers Roy. Soc.,” Vol. I. pp. 697–701; Biog.
Sketch by P. L. Möller, “Oersted’s Character und Leben,” 1851,
also Hauch und Forchammer, 1853; Obituary notice in _Jour.
Frankl. Inst._, 1851, Vol. XXI. p. 358; Humboldt, “Cosmos,”
1849, Vol. I. pp. 182, 185 and the 1819–1820 entry of “Magnetic
Observations,” in Vol. V; “Oversigt over det Kongl. danske
Videnskabernes Selskabs Fordhandlinger” for 1822, 1832,
1834–1835, 1836–1837, 1840–1842, 1847–1849; Poggendorff’s
_Annalen_, Vol. LIII; “Ursin’s Magaz. f. Kunstnere ...” Vols.
I and II; “Dict. of Electromagn.,” 1819; Sturgeon’s _Annals of
Electricity_, Vol. I. p. 121; Hatchett “On the Experim. ... of
Oersted and Ampère” (_Phil. Mag._, Vol. LVII. p. 40), _Phil.
Mag._, Vols. LVI. p. 394; LVII. pp. 47–49; LIX. p. 462; _Phil.
Mag._ or _Annals_, Vol. VIII. p. 230; _Annales de Chimie_
for Aug. 1820, p. 244; S. S. Eyck, “Over de magnetische ...”
(_Bibl. Univ._, 1821); Translation by H. Sebald, of H. C.
Oersted’s “Leben,” 1853; Michaud, “Biog. Univ.,” Vol. XXXI.
p. 196; P. L. Möller, “Der Geist in der Natur” (”The Spirit
in Nature”); Elie de Beaumont, “Memoir of Oersted” (“Smith.
Rep.” for 1863); Gilbert’s _Annalen_, Vol. LXVI. p. 295, 1820;
Callisen, “Medicinisches Schriftseller-Lexikon”; W. Sturgeon’s
“Sci. Researches,” Bury, 1850, p. 8 (for 1807), and pp. 9–12
for English version of Oersted’s pamphlet which was translated
in German in Vol. XXIX of Schweigger’s “Journal,” as well as
in Vol. LXVI of Gilbert’s _Annalen_, and which appeared in
French in Vol. XIV of the _Annales de Chimie et de Physique_
for 1820, as well as in Vol. II. pp. 1–6 of “Collection de
Mémoires relatifs à la Physique,” Paris, 1885. See also “Biogr.
Gén.,” Vol. XXXVIII. pp. 522–535; “Göttinger Gelehrte Anz.,”
No. 171; Sturgeon’s “Sc. Researches,” pp. 17, 18, 28, 415;
Thomson’s “Annals of Philosophy,” Vol. XVI. p. 375 for second
series of observations; Van Marum on “Franklin’s Theory of
Electricity,” pp. 440–453; “Galvanism,” by Mr. John Murray, p.
467; “Note sur les expériences ... de Oersted, Ampère, Arago,
et Biot,” (_Annales des Mines_, 1820); L. Turnbull, “Elec. Mag.
Tel.,” 1853, pp. 45, 221; J. F. W. Herschel’s “Preliminary
Discourse,” 1855, pp. 244, 255; Fahie, “Hist. Elec. Tel.,” 1884,
pp. 270–275, Harris, “Rud. Elec.,” 1853, p. 171; Ostwald’s
_Klassiker_, No. 63 and “Elektrochemie,” 1896, p. 67; Mrs.
Somerville, “Con. of Phys. Sci.,” 1846, p. 314; Noad, “Manual,”
p. 642; “Lib. Useful Know.” (El Magn.), pp. 4, 79; Lardner’s
“Lectures,” 1859, Vol. II. p. 119; Tomlinson’s “Cycl. Useful
Arts,” Vol. I. p. 559; Ure’s “Dict. of Arts,” 1878, Vol. II.
p. 233; Henry Martin’s article in Johnson’s “New Cyclopædia,”
1877, Vol. I. pp. 1512, 1514; “Nyt Biblioth. f. Physik,” Band I
auch Scherer’s Nord. Arch., II; “Tidskrift f. Natur ...” I 1822:
Schumacher’s “Astron. Jahrbuch” for 1838; L. Magrini, “Nuovo
metodo ...” Padova, 1836; Boisgeraud “On the Action of the
Voltaic Pile ...” (_Phil. Mag._, Vol. LVII. p. 203); _Sci. Am.
Suppl._, No. 454, p. 7241; Schweigger’s _Journal_, Vols. XXXII,
XXXIII, LII; Figuier, “Expos. et Hist.,” 1857, Vol. IV. p. 393;
“Engl. Cycl.,” “Arts and Sci.,” Vol. III. p. 782; Brande’s
“Man. of Chem.,” London, 1848, Vol. I. p. 248; Prime’s “Life
of Morse,” pp. 264, 451; Dr. Henry’s “Elm. of Exper. Chem.,”
London, 1823, Vol. I. pp. 193–203; _Jour. of the Frankl. Inst._
for 1851, Vol. XXI. p. 403; “_La Lumière Electrique_” for Mar.
19, 1887, p. 593, and for Oct. 31, 1891, pp. 201, etc.: Sir
William Thomson, “Math. Papers,” reprint, etc., 1872; “Encyl.
Metrop.” (Elect. Mag.,); G. B. Prescott, “Elect. and the El.
Tel.,” 1885, Vol. I. p. 91; “Smithsonian Report” for 1878,
pp. 272, 273, note; Bacelli (L. G.), “Risultati ...” Milano,
1821; “Bibl. Britan.,” Vol. XVII, N.S. p. 181; Vol. XVIII, N.S.
p. 3; “Edin. Phil. Journal,” Vol. X. p. 203; “Journal of the
Soc. of Tel. Eng.,” 1876, Vol. V. pp. 459–464, for a verbatim
copy of Oersted’s original communication on his discovery of
electro-magnetism, and pp. 464–469 for a translation thereof
by the Rev. J. E. Kempe under the title of “Experiments on the
effect of electrical action on the Magnetic Needle.” For the
interesting electro-magnetic experiments of J. Tatum, at this
same period, consult the _Phil. Mag._, Vol. LVII, 1821, p.
446; Vol. LXI, 1823, p. 241; Vol. LXII, 1823, p. 107, and, for
additional investigation, the Vols. XLVII and LI for years 1816
and 1818.
=A.D. 1820.=--On Oct. 9, M. Boisgeraud, Jr., reads, before the French
Académie des Sciences, a paper concerning many of his experiments,
which prove to be merely variations of those previously made by Oersted.
He observed that connecting wires, or arcs, placed anywhere in the
battery, affect the needle, and he noticed the difference of intensity
in the effects produced when electrical conductors are employed to
complete the circuit. He proposed to ascertain the conducting power
of different substances by placing them in one of the arcs, cells or
divisions of the battery, and bringing the magnetic needle, or Ampère’s
galvanometer, toward another arc, viz. to the wire or other connecting
body used to complete the circuit in the battery. With regard to
the positions of the needle and wire, as observed by Boisgeraud,
they are all confirmatory of Prof. Oersted’s statement (“Ency. Met.”
(Electro.-Mag.), Vol. IV. p. 6).
One month later, Nov. 9, 1820, Boisgeraud reads, before the same
Académie, his paper “On the Action of the Voltaic Pile upon the
Magnetic Needle,” which will be found on pp. 203–206 and 257, 258, Vol.
LVII of the _Philosophical Magazine_.
=A.D. 1820.=--Banks (Sir Joseph) (1743–1820), a very eminent
English naturalist and traveller, to whom reference has been made
under the A.D. 1775 date, deserves mention here were it alone
for the fact that while occupying the presidential chair of the Roy.
Soc., during the extraordinary long and unequalled period of over
_forty-two years_ (1777, date of Sir John Pringle’s retirement,
to 1820, the date of President Banks’ death) he was instrumental in
bringing prominently before the world many of the most important
discoveries and experiments known in the annals of magnetism and
electricity.
Sir Joseph Banks was succeeded in the presidency of the Royal Society
by William Hyde Wollaston, M.D., June 29, 1820, and by Sir Humphry
Davy, Bart., Nov. 30, 1820, the last named holding the office seven
years (R. Weld, “Hist. Roy. Soc.,” 1848, Vol. II. p. 359). Banks and
Dr. Solander, the pupil of Linnæus, had sailed (1768–1771) with Captain
Cook in his voyage around the globe, in the capacity of naturalists,
and afterwards (1772) visited Iceland, where they made many important
discoveries. In 1781 Banks was created a baronet; he received the Order
of the Bath in 1795 and subsequently had many honours conferred upon
him by different English and foreign societies. It is said that he was
never known to be appealed to in vain by men of science, either for
pecuniary assistance or for the use of his extensive library.
REFERENCES.--Tilloch’s _Phil. Mag._ for 1820, Vol. LVI. pp.
40–46; “Cat. Sci. Papers Roy. Soc.,” Vol. I. p. 176; Dr. Thomas
Thomson, “Hist. Roy. Soc.,” London, 1812, p. 12; _Gentleman’s
Magazine_ for 1771, 1772 and 1820; “Biog. Univ.,” Vol. LVII,
Suppl. p. 101; Larousse, “Dict. Univ.,” Vol. II. p. 155; “Eloge
Historique de Mr. J. Banks, lu à la Séance de l’Académie Royale
des Sciences, le 2 Avril 1821”; Sir Everard Home, “Hunterian
Oration,” Feb. 14, 1822. See besides, the _Phil. Mag._, Vol.
LVI. pp. 161–174, 241–257, for “A review of some of the leading
points in the official character and proceedings of the late
President of the Royal Society,” contrasting the respective
personal merits and achievements of Sir John Pringle and of Sir
Joseph Banks; “Lives of Men of Letters and Science,” by Henry,
Lord Brougham, Philad., 1846, pp. 199–229, 294–295.
=A.D. 1820.=--Barlow (Peter), F.R.S. (1776–1827), who taught
mathematics at the Military Academy of Woolwich from 1806 to 1847,
brings out the first edition of his “Essay on Magnetic Attractions,
Particularly as Respects the Deviation of the Compass on Shipboard
Occasioned by the Local Influence of the Guns, etc., with an Easy
Practical Method of Observing the Same in all Parts of the World.”
One of his biographers states that through this valuable publication,
which received the Parliamentary reward from the then existing Board
of Longitude, as well as presents from the Russian Emperor, he was
the first to reduce to strictly mathematical principles the method of
compensating compass errors in vessels (_Edin. Jour. of Sci._,
London, 1826, Vols. I. pp. 181, 182; II. p. 379).
This work contains the results of the many experiments to ascertain
the influence of spherical and other masses of iron upon the needle,
which Barlow instituted, more particularly after Prof. Hansteen’s
investigations became generally known. Sir David Brewster details
Barlow’s work in the “Encycl. Brit.,” and refers to the separate
observations of Mr. Wm. Wales (at A.D. 1774), Mr. Downie (at A.D.
1790), Captain Flinders (at A.D. 1801), and Charles Bonnycastle (at
A.D. 1820), mentioning the fact that it is to Mr. W. Bain we owe the
distinct establishment and explanation of the source of error in the
compass arising from the attraction of all the iron on board of ships.
The small 140-page book which Mr. Bain published on the subject in 1817
is entitled “An Essay on the Variation of the Compass, Showing how Far
it is Influenced by a Change in the Direction of the Ship’s Head, with
an Exposition of the Dangers Arising to Navigators from not Allowing
for this Change of Variation.” Brewster remarks that additional light
was thrown upon Mr. Bain’s observations by Captains Ross, Parry and
Sabine, but that we owe to Prof. Barlow alone a series of brilliant
experiments which terminated in his invention of the neutralizing
plate for correcting in perfect manner this source of error in the
compass (Noad’s “Manual,” pp. 531, 532; Olmstead’s “Introduct. to Nat.
Hist.,” 1835, pp. 206, 210). The simple contrivance therein alluded to
is described and illustrated at pp. 9 and 90–91 of the “Britannica,”
article on “Navigation,” and may briefly be said to consist of only a
thin circular plate of iron placed in a vertical position immediately
behind the binnacle or compass (Fifth Dissertation of “Britannica,”
Vol. I. p. 745, and article “Seamanship,” in Vol. XX. p. 27). Such
plates were immediately tried in all parts of the world and were at
once applied to the English vessels “Conway,” “Leven” and “Barracouta”
(_Trans. Soc. of Arts_ for 1821, Vol. XXXIX. pp. 76–100; Harris’ “Rud.
Mag.,” III. pp. 69–76; John Farrar, “Elem. of El. ...” 1826, pp.
376–383; _Westminster Review_ for April 1825; “Encycl. Metropol.,” Vol.
III (Magnetism), pp. 743, 799).
For Mr. Barlow’s experiments on the influence of rotation upon magnetic
and non-magnetic bodies, the result of which was communicated by him
to the Royal Society, April, 14, 1825, six days before the receipt of
S. H. Christie’s paper “On the Magnetism of Iron, Arising from its
Rotation,” communicated by J. F. W. Herschel, see pp. 10, 33, 34, of
the “Britannica,” Vol. XIV above referred to (_Edin. Jour. of Science_,
1826, Vols. III. p. 372, and V. p. 214. Consult also, J. Farrar, “Elem.
of El.,” 1826, pp. 387–395. For his extensive observations regarding
the influence of heat on magnetism and relative to the variation, as
well as for the mode of constructing his artificial magnets, consult
the same volume of the “Britannica,” at pp. 35, 36, 50–53 _et seq._ and
p. 73. See likewise, for the variation, Dr. Thomas Thomson’s “Outline
of the Sciences,” London, 1830, pp. 549–556; Harris, “Rud. Mag.,” I,
II. pp. 152–153. For Samuel Hunter Christie, consult “Abstracts of
Papers ... Roy. Soc.,” Vol. II. pp. 197, 225, 243, 251, 270, 305, 321,
347 and 351).
The new variation chart which Prof. Barlow constructed and in which
he embraced the magnetic observations made in 1832 by Sir James Ross,
R.N., is described and illustrated in _Phil. Trans._ for 1833, pp.
667–675, Plates XVII, XVIII. He remarks that the very spot where his
officer found the needle perpendicular, “that is, the pole itself, is
precisely that point in my globe and chart in which, by supposing all
the lines to meet, the several curves would best preserve their unity
of character, both separately and conjointly as a system” (eighth
“Britan.,” Vol. XIV, note, p. 50; Noad, “Manual,” p. 617; D. Olmstead,
“Intr. to Nat. Phil.,” 1835, p. 192).
Mr. Barlow’s electro-magnetic globe was exhibited by Dr. Birkbeck in
his lectures on “Electro-Magnetism” at the London Institution, May
26, 1824. (Its construction is fully described, more particularly, at
p. 65 of the English “Encycl. Brit.” (Magnetism); p. 91 of the “Lib.
of Useful Knowledge” (Electro-Magnetism); pp. 139–140, Vol. I of the
_Edin. Jour. of Science_, London, 1826, and pp. 120–122, Part III of
Harris’ “Rud. Mag.”) Its purpose was to show that what had hitherto
been considered as the magnetism of the earth might be only modified
electricity, and it was also intended to illustrate the theory advanced
by M. Ampère, who, as is well known, attributed all magnetic phenomena
to electric currents. In the words of Dr. Brewster:
“Barlow considers it as probable that magnetism as a distinct quality
has no existence in Nature. As all the phenomena of terrestrial
magnetism can be explained on the supposition that the magnetic power
resides on its surface, it occurred to Mr. Barlow that if he could
distribute over the surface of an artificial globe a series of galvanic
currents in such a way that their tangential power should everywhere
give a corresponding direction to the needle, this globe would exhibit,
while under electrical induction, all the magnetic phenomena of the
earth upon a needle freely suspended above it. Mr. Barlow says ‘he
has proved the existence of a force competent to produce all the
phenomena without the aid of any body usually called magnetic,’ yet
he acknowledges that ‘we have no idea how such a system of currents
can have existence on the earth, because, to produce them, we have
been obliged to employ a particular arrangement of metals, acids, and
conductors.’”
Barlow was the first to test the practicability of Ampère’s suggestion
that by sending the galvanic current through long wires connecting two
distant stations, the deflections of enclosed magnetic needles would
constitute very simple and efficient signals for an instantaneous
telegraph (_Ann. de Chimie et de Phys._, 1820, Vol. XV. pp. 72, 73). He
has thus stated the result: “In a very early stage of electro-magnetic
experiments, it had been suggested (by Laplace, Ampère and others) that
an instantaneous telegraph might be established by means of conducting
wires and compasses. The details of this contrivance are so obvious,
and the principle on which it is founded so well understood, that there
was only one question which could render the result doubtful; and this
was, is there any diminution of effect by lengthening the conducting
wires? It had been said that the electric fluid from a common (tinfoil)
electric battery had been transmitted through a wire four miles in
length without any sensible diminution of effect, and, to every
appearance, instantaneously; and if this should be found to be the case
with the galvanic circuit, then no question could be entertained of
the practicability and utility of the suggestion above adverted to. I
was therefore induced to make the trial; but I found such a sensible
diminution with only 200 feet of wire, as at once to convince me of the
impracticability of the scheme. It led me, however, to an inquiry as
to the cause of the diminution, and the laws by which it is governed.”
This passage is quoted in “Smithsonian Report” for 1878, p. 279; Fahie,
“Hist. El. Tel.,” p. 306; “Memor. of Jos. Henry,” 1880, pp. 223, 224,
the last named containing the following footnote: “On the Laws of
Electro-Magnetic Action,” _Edinburgh Philosophical Journal_, Jan.,
1825, Vol. XII. pp. 105–113:
“In explanation and justification of this discouraging judgment from
so high an authority in magnetics, it must be remembered that both in
the galvanometer and in the electro-magnet, the coil best calculated to
produce large effects was that of least resistance; which unfortunately
was not that best adapted to a long circuit. On the other hand the most
efficient magnet or galvanometer was not found to be improved in result
by increasing the number of galvanic elements. Barlow in his inquiry as
to the law of diminution was led (erroneously) to regard the resistance
of the conducting wire as increasing in the ratio of _the square_
root of its length” (pp. 110, 111 of the last-cited “Journal.)”]
Mr. Taylor justly adds that subsequent experiments have proved Ohm’s
law (announced three years after Barlow’s) of a simple ratio of
resistance to length as approximately correct.
REFERENCES.--G. B. Prescott, “The Speaking Telephone,” 1879,
II; _Sci. Am. Supp._, Nos. 405, p. 6466; 453, p. 7235; 547, p.
8735: “Mem. of Jos. Henry,” 1880, pp. 83, 94, 144, 485, 487.
See also, Poggendorff, Vol. I. pp. 102, 103; Whewell, “Hist.
Ind. Sciences,” 1859, Vol. II. pp. 223, 224, 245, 254, 616;
“Lib. Useful Knowledge” (Magnetism), p. 86 and (El. Mag.), pp.
7, 18, 22, 28; Sturgeon’s “Sci. Researches,” Bury, 1850, pp.
26, 29, 31, 298; Humboldt, “Cosmos,” 1849, Vol. I. p. 183; Mrs.
Somerville, “On the Earth not a Real Magnet,” in the “Conn. of
the Phys. Sci.,”; _Phil. Mag._, Vols. LV. p. 446; LX. pp. 241,
343; LXII. p. 321; Harris, “Rud. Mag.,” Part III. pp. 114–116;
“Encycl. Metropol.,” Vol. IV (Elect. Mag.), pp. 1–40; “Abstracts
of papers ... Roy. Soc.,” Vol. II. pp. 164, 197, 241, 318; “Cat.
Sc. Papers ... Roy. Soc.,” Vol. I. pp. 182–184; “Bibl. Britan.,”
Vol. XX, N.S. p. 127; “Edin. Phil. Journal,” 1824, Vol. X. p.
184 (alludes to papers of Barlow and Christie in _Phil. Trans._
for 1823, Part II).
Mr. Wm. Henry Barlow, second son of Peter Barlow, is the author of a
treatise, “On the spontaneous electrical currents observed in the wires
of the electric telegraph,” which was published in London during 1849
and appeared in Part I of the _Phil. Trans._, for that year. He is also
the inventor of a new electrical machine alluded to herein at Hare
(A.D. 1819), also at p. 130 of the “Annual of Sc. Disc.,” at pp. 76–77
of Noad’s “Manual,” and at p. 428, Vol. XXXVII of the “Philosophical
Magazine.”
=A.D. 1820.=--Laplace (Pierre Simon, Marquis de) (1749–1827), a
very distinguished French astronomer and mathematician, suggests for
telegraphic purposes the employment of magnetic needles suspended in
multipliers of wire, in place of the voltameters of Sömmering, and on
the 2nd of October 1820 his theory is thus explained by Ampère in a
paper read before the French Academy of Sciences:
“According to the success of the experiment to which Laplace drew my
attention, one could, by means of as many pairs of live wires and
magnetic needles as there are letters of the alphabet, and by placing
each letter on a separate needle, establish, by the aid of a distant
pile, and which could be made to communicate by its two extremities
with those of each pair of conductors, a sort of telegraph, which
would be capable of indicating all the details that one would wish to
transmit through any number of obstacles to a distant observer. By
adapting to the battery a keyboard whose keys were each marked with
the same letters and establishing connection (with the various wires)
by their depression, this means of correspondence could be established
with great facility, and would only occupy the time necessary for
pressing down the keys at the one station and to read off the letters
from the deflected needles at the other.”
Laplace is, perhaps, best known by his “Traité de Mécanique Céleste,”
the sixteen books and supplements to which are by many considered, next
to Newton’s “Principia,” the greatest of astronomical works; a book
which has been truly said to have had no predecessor and which has been
called the crowning glory of Laplace’s scientific career. His next
important work was the “Théorie Analytique des Probabilités,” the most
mathematically profound treatise on the subject which had yet appeared,
while his “Système du Monde” was called by Arago “one of the most
perfect monuments of the French language.” By Prof. Nichols, Laplace is
called “the titanic geometer”; by Mr. Airy “the greatest mathematician
of the past age”; by Prof. Forbes “a sort of exemplar or type of the
highest class of mathematical natural philosophers of this, or rather
the immediately preceding age.”
Laplace also wrote, in conjunction with Lavoisier, a treatise “On the
Electricity which Bodies Absorb when Reduced to Vapor” (_Mém. de
Paris_ for 1781). Prof. Denison Olmstead, treating of the origin
of atmospherical electricity (“Introd. to Nat. Phil.,” 1835, pp.
158, 159), says: “Among the known sources of this agent none seems
so probable as the evaporation and condensation of watery vapor. We
have the authority of two of the most able and accurate philosophers,
Lavoisier and Laplace, for stating that bodies in passing from the
solid or liquid state to that of vapor, and, conversely, in returning
from the aeriform condition to the liquid or solid state, give
unequivocal signs of either positive or negative electricity,” and he
adds, in a footnote:
“M. Pouillet has lately published a set of experiments, which seems to
overturn Volta’s theory of the evolution of electricity by evaporation.
He has shown that no electricity is evolved by evaporation unless
some chemical combination takes place at the same time ...” (Thomson,
“Outlines,” p. 440) ... “But we shall be slow to reject the results of
experiments performed by such experimenters as Lavoisier and Laplace,
especially when confirmed by the testimony of Volta and Saussure.”
With regard to the origin of meteorites, Laplace has advanced the very
bold theory that they may be products of Lunar volcanoes, and Prof.
Lockhart Muirhead stated that he would “present the reasoning upon
which this extraordinary hypothesis is founded in the popular and
perspicuous language of Dr. Hutton, of Woolwich: the respect due to the
name of Laplace justifying the length of the extract,” which he gives
at pp. 633–635, Vol. XIV of the 1857 “Britannica.”
REFERENCES.--Humboldt, “Cosmos,” London, 1849, Vol. I. pp.
108–109; Young, “Course of Lectures,” London, 1807, Vol. II.
p. 501, alluding to “Zach. Mon. Corr.,” VI. p. 276, also
to Gilbert, XIII. p. 353, 108, and stating that Olbers had
suggested Laplace’s idea in 1795. See “Mem. of the Astronom.
Soc. of London,” Vol. III. p. 395: Laplace, “Mem. de l’Institut”
for 1809, p. 332; Dr. Young’s “Course of Lectures,” 1807, Vol.
I. pp. 249, 250, 522; Vol. II. p. 466; Humboldt, “Cosmos,”
London, 1849, Vol. I. pp. 28, 76, 130; Vol. II. p. 712;
Lavoisier at A.D. 1781: Biot at A.D. 1803; _Annal. de Ch. et
Phys._, Vol. XV. pp. 72, 73, and for Laplace and Lavoisier, see
Delaunay, “Manuel ...” 1809, p. 178; “Mem. de l’Acad. des Sc.,”
for 1781; “Journal des Savants,” for Feb. 1850 and Nov. 1887;
Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 184; “Cat. Sc.
Pap. Roy. Soc.,” Vol. III. pp. 845–848; Johnson’s “Cyclopædia,”
pp. 1647–1650 and the “First Supplement,” p. 62.
For Laplace and Joseph Louis Lagrange, see “Mémoires de
l’Institut,” Vol. III. p. 22; also “Pioneers of Science,” by
Sir Oliver Lodge, London, 1905, Lecture XI, and for Lagrange,
consult “Journal des Savants,” Sept. 1844, May 1869, August
1878, Sept. 1879, Sept. 1888 and Oct. 1892.
M. Cyrille Pierre Théodore Laplace, captain in the French navy,
is the author of the “Voyage Autour du Monde ... sur la Corvette
_Favorite_ ...” and of “Campagne de Circumnavigation de la Frégate
_l’Artémise_ ...” published in Paris during the years 1833, 1839
and 1841.
Baron Jean Baptiste Fourier, celebrated French physicist (1768–1830)
who, in 1827, succeeded Laplace as head of the Council of the
Ecole Polytechnique (“Biog. Gén.,” Vol. XVIII. p. 346) says of his
predecessor:
“Posterity, which has so many particulars to forget, will little care
whether Laplace was for a short time minister of a great state. The
eternal truths which he has discovered, the immutable laws of the
stability of the world, are of importance, and not the rank which he
occupied” (C. R. Weld, “Hist. Roy. Soc.,” Vol. II. p. 465). Fourier is
the author of “Expériences thermo-électriques” (“Encycl. Brit.,” ninth
ed., Vol. IX. p. 490; “Eng. Cycl.,” Biography, Vol. II. p. 977).
=A.D. 1820.=--Dutrochet (René Joachim Henri) (1776–1847) a
distinguished French natural philosopher, and likewise medical adviser
to the King of Spain, Joseph Bonaparte, publishes an interesting
treatise on meteors, in conjunction with Mr. Nathaniel Bowditch, who
had already written many very able papers on astronomical subjects and
who afterwards translated the “Mécanique Céleste” of Laplace. Eight
years later (1828) appeared Dutrochet’s “Nouvelles Recherches ...”
wherein he attributes to electricity the direction taken by fluids
through animal and vegetable membranes. The passage of a fluid from
without inwardly he called _endosmosis_, and the passage of the
fluid from within outwardly he termed _exosmosis_.
Of Dutrochet, Dr. John Hutton Balfour, of Edinburgh, makes mention
when treating of the temperature of plants. He thus expresses himself:
“While the nutritive processes are going on in the plant, there is a
certain amount of heat produced. This, however, is speedily carried
away by evaporation and other causes, and it is not easily rendered
evident. Dutrochet, by means of Becquerel’s thermo-electric needle,
showed an evolution of heat in plants. In doing this, he prevented
evaporation by putting the plant in a moist atmosphere. In these
circumstances the temperature of the active vegetating parts, the
roots, the leaves, and the young shoots, indicated a temperature above
the air of ½ to ¾ of a degree Fahrenheit. Van Beek and Bergsma, in
their experiments on the _Hyacinthus Orientalis_ and the _Entelea
Arborescens_, found the proper heat of the active parts of plants about
1·8° F. above that of the air. The vital or proper heat of plants,
according to Dutrochet, is found chiefly in the green plants, and it
undergoes a quotidian paroxysm, reaching the maximum during the day,
and the minimum during the night. When stems become hard and ligneous,
they lose this vital heat. Large green cotyledons gave indications of
a proper heat. The hour of quotidian maximum varied from 10 a.m. to 3
p.m. in different plants.”
It is stated by Becquerel that in the act of vegetation, the earth
acquires continually an excess of positive electricity, while the bark
and part of the wood receive an excess of negative electricity. The
leaves act like the green part of the parenchyma of the bark--that is
to say, the sap which circulates in their tissues is negative with
relation to the wood, to the pith, and to the earth, and positive with
regard to the cambium. The electric effects observed in vegetables are
due to chemico-vital action, and he asserts that the opposite electric
states of vegetables and of the earth give reason to think that, from
the enormous vegetation in certain parts of the globe, they must exert
some influence on the electric phenomena of the atmosphere.
REFERENCES.--Gmelin’s “Chemistry,” Vol. I. p. 447; “Biog.
Gén.,” Vol. XV. p. 506; Poggendorff, “Annalen,” Vol. I. p. 663;
Larousse, “Dict. Univ.,” Vol. VI. p. 1448; J. W. Ritter, in
“Denkschr. d. Münch. Acad.” for 1814, and the eighth ed. of the
“Ency. Brit.” Vol. XXI. p. 635, for observations concerning the
_mimosa pudica_ and the _mimosa sensitiva_; “Cat. Sc. Papers
Roy. Soc.,” Vol. II. pp. 422–425; Vol. VI. p. 646; Vol. VII. p.
584; Poggendorff, Vol. I. p. 633; “Observations on the diurnal
variation of the magnetic needle,” in Sturgeon’s “Annals,” Vol.
VII. pp. 369–370, and in the _Comptes Rendus_, Vol. XII. p.
298, of Feb. 8, 1841; Burnet, “On the motion of sap in plants.
Researches of Dutrochet on Endosmose and Exosmose ...” London,
1829 (“Phil. Mag. or Annals,” Vol. V. p. 389).
=A.D. 1820.=--Fresnel (Augustin Jean) (1788–1827), one of the most
distinguished French mathematicians and natural philosophers,
communicates a paper detailing his experiments for decomposing water by
means of a magnet. He produced a current in an electro-magnetic helix
enclosing a bar-magnet covered with silk, and on plunging the ends of
the wire in water he observed some very remarkable effects which are
set forth in the _Annales de Chimie et de Phys._, series 2, Vol. XV. p.
219.
REFERENCES.--“Eloge de Fresnel,” by Arago, in his “Œuvres,” Vol.
I; Account of Fresnel’s life in the “Biog. Univ.;” Whewell,
“Hist. of Induc. Sci.,” 1859, Vol. II. pp. 96, 102, 114–117;
“Œuvres complètes d’Augustin Fresnel, publiées par les soins du
Ministre de l’Instruction Publique,” Paris, 1870, in three vols.
=A.D. 1820.=--Sir Richard Phillips (1778–1851), communicates, July
11, to the _Philosophical Magazine_ (Vol. LVI. pp. 195–200) a very
interesting paper entitled “Electricity and Galvanism Explained on
the Mechanical Theory of Matter and Motion.” After reviewing the then
existing theories, he concludes by saying:
“Electricity is no exception to the mechanical principles of matter
and motion, and in regard to the kindred phenomena of galvanism, I
will content myself with observing that it is merely _accelerated
electricity_, the interposing fluid being palpably decomposed and
evolving the electrical powers, each term in the series of plates being
a new impulse or power added to the previous one, till the ultimate
effect is accelerated, like that of a body falling by the continuous
impulses of the earth’s motions, or like a nail heated red-hot by
accelerations of atomic motion produced by repeated percussions of a
hammer.”
Consult “Bibl. Ital.,” Vol. XXVII. p. 107 for references to the “Annals
of Philosophy,” in which he mentions an experiment upon a young poplar,
“whereby it would seem that copper was imbibed in the branches, etc.,
from a solution placed at its roots, and that it was precipitated on a
knife used to cut off a branch.”
=A.D. 1820.=--Brewster (Sir David) (1781–1868), a very distinguished
English natural philosopher and writer, who had just founded the
“Edinburgh Philosophical Journal” in conjunction with Prof. Robert
Jameson, announces his discovery of the existence of two poles of
greatest cold on opposite sides of the northern pole of the earth.
By this he was, like other authors, led to the belief that there
might be some connection between the magnetic poles and those of
maximum cold, and he remarks (Noad “Manual,” London, 1859, p. 545,
and article “Magnetism” in “Encycl. Brit.”): “Imperfect as the
analogy is between the isothermal and magnetic centres, it is yet too
important to be passed over without notice. Their local coincidence
is sufficiently remarkable, and it would be to overstep the limits of
philosophical caution to maintain that they have no other connection
but that of accidental locality; and if we had as many measures of
the mean temperature as we have of the variation of the needle, we
might determine whether the isothermal poles were fixed or movable.”
Similar opinions entertained by Dr. Dalton, Dr. Traill and Mr. Christie
are also mentioned by Noad, who quotes from Oersted’s treatise on
“Thermo-Electricity” the statement of the Danish philosopher “that the
most efficacious excitation of electricity upon the earth appears to be
produced by the sun, causing daily evaporation, deoxidation and heat,
all of which excite electrical currents.”
From his able paper in the _Edinburgh Philosophical Transactions_
for 1820, one is led to share Sir David Brewster’s belief “that two
meridians of greatest heat and two of greatest cold are called into
play, and that the magnetism of our globe depends in great measure
upon electro or rather thermo-magnetic currents.” The electro-magnetic
hypothesis was, he says, ably supported by Prof. Barlow in his paper
“On the probable electric origin of all the phenomena of terrestrial
magnetism,” communicated to the _Phil. Trans._ for 1831. Brewster
thus locates the two poles of maximum cold: The American pole in N.
Lat. 73, and W. Long. 100 from Greenwich, a little to the East of Cape
Walker; the Asiatic pole in N. Lat. 73 and E. Long. 80, between Siberia
and Cape Matzol, on the Gulf of Oby. Hence the two warm meridians will
be in W. Long. 10 and E. Long. 170, and the two cold meridians in W.
Long. 100 and E. Long. 80.
As has already been indicated (under A.D. 1717, Leméry), Sir David
Brewster was the discoverer of the pyro-electrical condition of the
diamond, the garnet, the amethyst, etc. His development of some of
Haüy’s experiments led to a similar discovery, attaching to several
mineral salts as well as to the plates and powders of the tourmaline,
of the scolezite and the melozite; and he likewise experimented with
the boracite, mesotype and with the several minerals and artificial
crystals detailed at pp. 208–215, Vol. I of the _Edin. Jour. of
Science_, London, 1826; and in Chap. II. s. 1, vol. viii of the eighth
“Encycl. Brit.,” article on “Electricity.”
At Part I. chap. i. s. 6 of the last-named article will be found
Brewster’s observations on the nature and origin of electrical light,
his latest researches having been made, like those of Joseph von
Fraunhofer (see A.D. 1814–1815), on the dark and on the luminous lines
which appear in the spectrum formed from it by a prism.
During the year 1831 appeared Brewster’s “Treatise on Optics,” his
“Life of Sir Isaac Newton,” and his “Letters on Natural Magic.” It
is in one of the chapters of the last-named work that he treats of
automatic talking machines and remarks: “We have no doubt that before
another century is completed a talking and a singing machine will be
numbered among the conquests of science.”
Brewster’s other scientific treatises are too numerous and cover too
wide a range to be enumerated here. The “Catal. of Sci. Papers of the
Roy. Soc.” (Vol. I. pp. 612–623) gives the titles of as many as 299
contributions made by him on important subjects, and he has had no less
than 76 papers in the first 39 parts of the _North British Review_, 30
in the _Phil. Trans._ and 28 in the _Edin. Review_. They appear, in
fact, in all the prominent publications of his time, and have won for
him leading honours, more especially from the Edinburgh and Aberdeen
Universities and the Scotch, Irish, English and French Societies, the
French Academy of Sciences doing him the signal honour of selecting him
as one of its eight foreign associates in place of Berzelius, deceased.
Conjointly with Davy, Herschel and Charles Babbage, he originated the
British Association during 1831, and it was in this same year that
he was knighted and decorated by King William IV. He had been made a
Fellow of the Royal Society of Edinburgh in 1808, and had during the
same year undertaken the editorship of the “Edinburgh Encyclopædia of
Sci., Lit. and Art.” This he continued for twenty-two years, after
which he edited the _Edin. Jour. of Sci._, and also entered with Taylor
and Phillips upon the editorship of the _London and Edin. Phil. Mag.
and Journal_. Many of our readers will doubtless be glad to know that
the last named was a continuation of the well-known _Philosophical
Magazine_ so often quoted in this “Bibliographical History.”
REFERENCES.--The obituary notice contributed by Dr. J. H.
Gladstone to the proceedings of the Royal Society; _Chemical
News_, Amer. reprint, Vol. II. pp. 198, 233; also p. 293 for
accounts given by Sir J. Simpson and Prof. Fraser; J. Robison
and Brewster, “A System of Mechan. Phil.,” London and Edin.,
1822; Ferguson and Brewster’s “Essays and Treatises on Astr.
Elect.,” etc., Edinburgh, 1823; Brewster’s several articles in
the “Encycl. Britannica,” 7th and 8th editions, on “Electricity
and Magnetism”; _Transactions of the Roy. Soc. of Edinburgh_,
Vols. IX. 1821; XX. Part IV; _Edin. Jour. of Sci._, Oct.
1824, No. 2, p. 213; Noad, “Manual,” London, 1859, pp. 31,
32, 636–638; Harris, “Magnetism,” Part III. p. 119; Whewell,
“Hist. of Induc. Sci.,” 1859, Vol. II. pp. 75, 81, 331, 332; the
lectures delivered by Wm. A. Miller during 1867 before the Royal
Institution of Great Britain.
Charles Babbage (1792–1871), a prominent English scientist who is
mentioned above and who besides being one of the founders of the Royal
Astronomical Society, as has already been stated, was also a founder
of the British Association and the originator of the Statistical
Society, is the author of valuable papers, exhibiting a wide range of
learning and research--mainly on mathematical subjects and relating to
magnetical and electrical phenomena--which have been published in the
Reports of the Royal and other Societies (“English Cycl.,” Vol. I. p.
457; “Encyl. Brit.,” ninth ed., Vol. III. p. 178; Larousse, “Dict.,”
Vol. II. pp. 5–6; account of Babbage’s work in C. R. Weld’s “Hist. Roy.
Soc.,” Vol. II. pp. 369–391).
=A.D. 1820.=--Fisher (George) (1794–1873), who two years before
had joined Captain David Buchan in his voyage to the Arctic regions, is
the first to point out the true cause of the sudden alteration in the
rates of chronometers at sea. “He observed,” says Dr. Roget, “that the
chronometers on board the ‘Dorothea’ and ‘Trent’ had a different rate
of going from that they had on shore, even when these vessels had been
frozen in, and therefore when their motion could not have contributed
to that variation; ... this effect could be attributed only to the
magnetic action exerted by the iron in the ships upon the inner rim
of the balance of the chronometers, which is made of steel. A similar
influence was perceptible on placing magnets in the neighbourhood of
the chronometers. This conclusion was confirmed by experiments made for
this purpose by Mr. Barlow, who ascertained that masses of iron devoid
of all permanent magnetism occasioned an alteration in the rates of
chronometers placed in different positions in their vicinity.”
REFERENCES.--Fisher’s article “On the Errors in Longitude as
Determined by Chronometers at Sea, Arising from the Action of
the Iron in the Ships upon the Chronometers,” communicated
by John Barrow, F.R.S., to the _Phil. Mag._, Vol. LVII. pp.
249–257. See besides, _Edinburgh Jour. Sci._, London, 1826, Vol.
V. p. 224; _Phil. Trans._ for 1820, Part. II. p. 196, and the
volume for 1833, relative to magnetical experiments; also the
“Lib. U. K.” (Magn.), p. 63. For Capt. Buchan, consult Barrow’s
“Chronological History of Voyages into the Arctic Regions.”
Mr. George Thomas Fischer (1722–1848) is the author of “A Practical
Treatise on Medical Electricity” (Poggendorff, Vol. I. p. 756).
=A.D. 1820.=--Bonnycastle (Charles), Professor of Mathematics in
the University of Virginia, treats of the distribution of the magnetic
fluids in masses of iron, as well as of the deviations which they
produce in compasses placed within their influence, at pp. 446–456,
Vol. LV of Tilloch’s _Philosophical Magazine_.
He refers to the then recent publication of Peter Barlow’s “Essay on
Magnetic Attractions,” containing the results of many experiments, made
principally upon spheres of iron, as well as to Dr. Young’s views of
the subject, which were printed by order of the Board of Longitude,
and he says that the principle upon which he intends establishing
his inquiry “is an extension of the law that regulates the action
of electrified bodies upon conductors; which was first given by M.
Poisson in the Memoirs of the Institute for 1811, and employed by him
to determine the development of the electric fluids in spheres that
mutually act on each other.”
The afore-named dissertation, at the time, called forth a rejoinder
from a correspondent and a further communication from Mr. Bonnycastle,
both of which appear at pp. 346–350, Vol. LVI of the same publication.
REFERENCES.--Silliman’s _Journal_, Vol. XL. p. 32; “Sketch of
the Life of Chas. Bonnycastle,” by Thomas Thomson; Poggendorff,
Vol. I. pp. 234, 235; article “Magnetism,” p. 9, Vol. XIV of the
eighth “Britannica.”
=A.D. 1820.=--Harris (Wm. Snow), member of the College of Surgeons, and
a very distinguished English scientist (1791–1867), proposes to the
Board of the Admiralty his system of lightning conductors, of which an
account appears at p. 231, Vol. LX of the _Phil. Mag._, as well as in
a separate work published at London during 1822. This is followed by
his “Observations on the Effects of Lightning ...” 1823, and by papers
relative to the defence of ships and buildings from lightning, which
were published, more particularly, in several numbers of the _Nautical
Magazine_, the _Phil. Mag._, the _Annals of Electricity_, and in the
_Proc. Lond. Elec. Soc._ for 1842, as well as in his “Record of Phil.
Papers,” and under separate heads during many years between 1827 and
1854. One of his biographers remarks:
“His researches have gone far to remove certain popular errors as to
what have been called ‘conductors’ and ‘non-conductors’ of electricity,
and to show the inutility of the old form of lightning rod in the
majority of cases; it being necessary, in place of such rod form, to
link into one great chain all the metallic bodies employed in the
construction of a building, thus providing a connection with these
conductors between the highest parts and the ground, the single
conductor, in one highest part, being possibly insufficient to divert
the course of the fluid and protect the whole fabric. These general
principles have been largely applied to the protection of the ships of
the Royal Navy during the last five and twenty years, under his advice
and direction; and, laying aside the opinions which had been commonly
received, the masts themselves of a ship have all been rendered
perfectly conducting by incorporating with the spars capacious plates
of copper, whilst all the large metallic masses in the hull have been
tied, as it were, into a general conducting chain, communicating with
the great conducting channels in the masts, and with the sea. This may
be considered as the greatest experiment ever made by any country in
the employment of metallic conductors for ships, and the result has
been to secure the navy from a destructive agent, and to throw new
light upon an interesting department of science” (Whewell, “Hist. of
Induc. Sci.,” Vol. II. pp. 199, 200; _Phil. Mag._ for March 1841;
eighth “Encycl. Britannica,” Vols. VIII. pp. 535, 610, 611, and XX. p.
24; “Edin. Review” for Oct. 1844, Vol. LXXX. pp. 444–473).
Harris was the first, says Brewster, who introduced accurate
quantitative measures into the investigation of the laws of statical
electricity--the unit measure by which quantity is minutely
estimated--and also the hydro-electrometer and scale-beam balance by
which its intensity and the laws of attractive forces at all distances
are demonstrated. Of not less value is the thermo-electrometer, by
which the heating effects of given quantities of electricity are
measured and rendered comparable with the varying conditions of
quantity and intensity. Besides these instruments, we owe to Harris
the discovery of a new reactive force, through which repulsion and
other small physical forces are investigated and determined by means
of his bifilar balance, founded upon the reactive force of two
vertically suspended parallel threads when twined upon each other at
a given angle, and acted upon by a suspended weight. With the aid of
these instruments he has carried on a variety of important inquiries
into the laws of electrical forces, and the laws and operations of
electrical accumulation (eighth “Brit.,” Vol. VIII. p. 535). His
papers on the subject appeared in 1825 and 1828, and a _résumé_
of them is given by Noad (“Manual” 1859, pp. 35, 137–140), as well
as in the “Electricity” article of the “Britannica,” both of which
contain descriptions and illustrations of Harris’ unit jar and
electro-thermometer.
During the year 1827 Mr. Harris published in the _Trans. Roy. Soc. of
Edinburgh_ his memoir entitled “Experimental Inquiries Concerning
the Laws of Magnetic Forces,” which experiments were made by means
of a new and very accurate apparatus invented by him for examining
the phenomena of induced magnetism. The above was followed by two
other memoirs, published in the _Phil. Trans._ for 1831, “On the
Influence of Screens in Arresting the Progress of Magnetic Action ...”
and “On the Power of Masses of Iron to Control the Attractive Force
of a Magnet,” which are discoursed of in the “Britannica” article on
“Magnetism,” wherein special treatment is also given more particularly
to Mr. Harris’ researches concerning artificial magnets as well as
the magnetic charge, the development of magnetism by rotation and the
phenomena of periodical variations (“Rudim. Mag.,” Part III. p. 60;
Fahie’s “Hist, of Elec. Tel.,” pp. 283, 284).
Besides additional apparatus named in the subjoined references Mr.
Harris invented a very effective steering compass, of which an account
is given in Part III. pp. 148–153, of his “Rudimentary Magnetism,”
as well as at p. 594 of Noad’s “Manual,” at p. 105 of the “English
Cyclopædia” (Arts and Sciences), Vol. III, and at p. 80, Vol. VIII,
1857, “Encycl. Britannica,” and he has also devised a magnetometer
for the measurement of electric forces, of which the description and
illustrations appear in the last-named publication as transcribed from
Mr. Harris’ work already mentioned.
Mr. Harris was made a F. R. S. in 1831, and received the Copley medal
four years later. It was in 1843 he published his well-known work “On
the Nature of Thunderstorms,” the plans he advocated being adopted in
1847, when he received the order of knighthood as well as a large money
grant from the English Government in acknowledgment of his scientific
services. The following appears in the obituary notice of Sir Wm. Snow
Harris, contributed by Mr. Charles Tomlinson to the _Proceedings of
the Roy. Soc._ (XVI, 1868):
“Harris’ sympathies were with the Bennetts, the Cavendishes, the
Singers, the Voltas of a past age. Frictional electricity was his
_forte_ and the source of his triumphs. He was bewildered and
dazzled by the electrical development of the present day, and almost
shut his eyes to it. He was attached too closely and exclusively to
the old school of science to recognize the broad and sweeping advance
of the new. He was not conscious even of being behind his age when
he presented to the Royal Society in 1861 an elaborate paper on an
improved form of Bennett’s discharger, and still less in 1864, when he
discussed the laws of electrical distribution, and yet relied upon the
Leyden jar and the unit jar.”
REFERENCES.--_Trans. of the Plymouth Institution_, also _Trans.
of the Roy. Soc._ for 1834, 1836, 1839; “Eng. Encycl.” (“Common
Electricity”), Vol. III. p. 801; W. A. Miller, “Elem. of Chem.,”
1864, p. 32. For descriptions of his bifilar balance see the
eighth “Britannica,” Vol. VIII. p. 623; Harris, “Rud. Elec.,”
p. 99, and “Rud. Magn.,” pp. 119, 120; Noad, “Manual,” pp. 26,
27, 37, 40, 41, 63, 580; C. Stahelin, “Die Lehre ...” 1852;
P. Volpicelli, “Ricerche analitiche ...” Roma, 1865, while,
for his balance electroscope and electrometers, see “Edin.
Phil. Trans.,” Dec. 1831; eighth “Britannica,” Vol. VIII. pp.
540, 590, 620 622, 624; Harris, “Rud. Elec.,” pp. 99, etc.;
the “Bakerian Lecture”; the “Report of British Association,”
Dundee, 1867, for an able account of electrometers by Sir
William Thomson. His electrical machine is described at pp.
74–76 of Noad’s “Manual,” as well as at p. 604, Vol. VIII
of the 8th “Britannica,” the latter also giving, at p. 550,
Harris’ experiments on the electrical attraction of spheres and
planes. “Catal. Sc. Papers Roy. Soc.,” Vol. III. pp. 191–192;
Lippincott’s “Biog. Dict.,” 1886, p. 1230; Biography in Harris’
“Frictional Electricity”; “Abstracts of Papers ... Phil. Trans.,
1800–1830,” Vol. II. p. 298; _Lumière Electrique_ for Oct. 3,
1891, p. 49; reprint of Sir Wm. Thomson’s “Mathematical Papers,”
1872; “Brit. Asso. Reports” for 1832, 1835, 1836; _Edin. Phil.
Trans._ for 1834; Fahie’s “History,” p. 321; _Edin. and London
and Edin. Phil. Mag._ for 1840; _Phil. Trans._, 1842; _Phil.
Mag._ for 1856–1857, and Harris’ “Manuals of Electricity,
Galvanism and Magnetism,” published in John Weale’s Rudimentary
Series.
=A.D. 1820.=--Mitscherlich (Eilardt--Eilhert), Professor of Chemistry
at the Berlin University, discovers what is called _Isomorphism_
(_isos_, equal; _morphe_, form), showing that bodies containing very
different electro-positive elements could not well be distinguished
from each other; it was impossible therefore to put them in distant
portions of the classification, and thus, remarks Whewell, the first
system of Berzelius crumbled to pieces.
In other words, Mitscherlich was the first to draw attention to the
fact that two bodies having the same composition could assume different
forms; to this law Berzelius gave the name of _Isomerism_ (_isos_,
equal; _meros_, part).
Sir John Herschel makes particular mention (“Treatise on Light,”
s. 1, 113) of Mitscherlich’s remarkable experiment with sulphate
of lime--the alteration in the tints of which by heat, it is said,
was first observed by Fresnel. This experiment was repeated by Sir
David Brewster, and he discovered still more curious properties in
_glauberite_, all of which are detailed in Vol. I. p. 417 of the
_London and Edinburgh Phil. Mag._ for Dec. 1832.
REFERENCES.--“Cat. Sci. Papers Roy. Soc.,” Vol. IV. pp. 413–416;
“Library Useful Knowledge” (Pol. of Light), p. 63; Poggendorff,
Vol. II. pp. 160, 161; the very able treatise of Mr. J. Beete
Jukes on “Mineralogical Science”; also Poggendorff’s _Annalen_,
Vol. XV. p. 630, for Mitscherlich on the chemical origin of iron
glance in volcanic masses.
=A.D. 1820.=--Ampère (André Marie) (1775–1836), one of the most
distinguished philosophers of the century, Professor of Mathematical
Analysis in the French Ecole Polytechnique (1809), afterwards Professor
of Physics at the Collège de France, reads before the Académie Royale
des Sciences, Sept. 18, 25, Oct. 9, 13, and Nov. 6, 1820, papers
containing a complete exposition of the phenomena of electro-dynamics.
His investigations were subsequently embodied in the “Recueil
d’Observations ...” Paris, 1822, and were still further developed
during 1824 and 1826, as shown through both his “Précis de la théorie
...” and “Théorie des Phénomènes Electro-Dynamiques.”
The news of Oersted’s discovery of the relation existing between
the electric current and the magnet--the fundamental fact of
electro-magnetism--was made known in July 1820, and the inquiry was
at once taken up more particularly by Ampère, Arago, Biot, and Félix
Savary in France, as well as by Berzelius, Davy, De la Rive, Cumming,
Faraday, Joseph Henry, Schweigger, Seebeck, Sturgeon, Nobili and others
throughout Europe and elsewhere. Of all these scientists, Ampère proved
the most energetic, and, within three months of the announcement of
Oersted’s discovery, his first memoir on the subject was publicly read
in Paris.
In this first paper, Sept. 18, he explains the law determining the
position of the magnetic needle in relation to the electric current,
and he also makes known his intended experiments with spiral or helical
wires, which he predicts will acquire and retain the properties of
magnets so long as the electrical current flows through them. He
likewise explains his theory of magnets, saying that if we assume a
magnet to consist of an assemblage of minute currents of electricity
whirling all with the same direction of rotation around the steel
molecules and in planes at right angles to the axis of the bar, we will
have an hypothesis which will account for all the known properties of a
magnet. He constructed his spirals and helices, and to the astonishment
of all, he produced magnets formed only of spools of copper wire
traversed by electric currents. We can readily imagine, adds Prof.
A. M. Mayer, the intense interest awakened by this discovery, a
discovery which caused Arago to exclaim, “What would Newton, Halley,
Dufay, Æpinus, Franklin and Coulomb have said if one had told them
that the day would come when a navigator would be able to lay the
course of his vessel without a magnetic needle and solely by means
of electric currents?” “The vast field of physical science,” says
Arago, “perhaps never presented so brilliant a discovery, conceived,
verified and completed with such rapidity.” Thus Ampère became the
author of a beautiful generalization, which not only included the
phenomena exhibited by the new combinations of Oersted, but also
disclosed forces existing in arrangements already familiar, although
they were never detected till it was thus pointed out how they were to
be looked for. His electro-dynamic theory of the action of currents
and of magnets has been thought worthy of a place near the Principia
of Newton ... it deservedly gained for him the title of the Newton of
electro-dynamics, as he did for this branch of science even more than
Coulomb had previously done for electro-statics (Profs. A. M. Mayer and
W. B. Rogers, “Memorial of Jos. Henry,” 1880, pp. 81, 476; Lardner,
“Lectures,” 1859, Vol. II. p. 120; Fahie, “Hist. Tel.,” p. 276).
The experiments of Oersted and Ampère were at once greatly extended
by many scientists, among whom may be especially mentioned MM.
Yelin, Bœckmann, Van Beek, De la Rive, Moll, Nobili, Barlow and
Cumming. The last named apparently gave the earliest notice of the
increased effects of a convolution of wire around the magnetic needle,
and constructed the first astatic needle galvanometer (_Trans.
Camb. Soc._, Vol. I. p. 279). The Chevalier Julius Konrad Yelin
(1771–1826), German mathematician, ascertained that the electricity
of an ordinary machine when passed along a helix, either in simple
electrical sparks or by discharges from a battery, has the effect
of rendering an included needle magnetic. According to Dr. Henry,
M. Bœckmann found in varying these experiments that no modification
of the effect is produced by altering the diameter of the helix
from half an inch to thirteen inches. With a helix of thirty-four
inches diameter, and a coated surface of 300 square inches, much less
magnetism was, however, imparted; and with one of eighty-four inches
it was scarcely perceptible. It was found that a needle outside of the
helix was magnetized as much as one within; that after being once fully
magnetized a continuation of the discharges diminished its power; and
that five jars, each of 300 square inches, did not produce, by repeated
discharges, much more effect than one of them (Poggendorff, Vol. II. p.
1382; Gilbert’s _Annalen_ for 1820–1823).
In his second paper, Sept. 25 (_Ann. de Chim. et de Phys._, Vol.
XV. pp. 59–170), Ampère makes known the results of his experiments on
the mutual attractions and repulsions of electrical currents, showing
conclusively that when the voltaic current is passed in the same
direction through two parallel wires, so placed as to move freely,
they attract each other, and that they are repelled if the currents
are passed in opposite directions. Thus he establishes the second
fundamental law of electro-magnetism, the first law, instituted as
we have seen by Oersted, being that the magnetical effect of the
electrical current is a circular motion around the current. In the
last-named paper he also proposes the hypothesis of currents of
electricity circulating from east to west around the terrestrial
globe in planes at right angles to the direction of the dipping
needle, to account for the phenomena of terrestrial magnetism (Roget,
“Electro-Magn.,” p. 47).
In his third paper, Oct. 9, Ampère investigates the properties of
currents transmitted through wires forming closed curves (_courbes
fermées_) or complete geometrical figures, an inquiry also alluded
to in another memoir read Oct. 30, 1820.
These papers were immediately followed by others, which engaged nearly
all the sittings of the Academy between Dec. 4, 1820, and Jan. 15,
1821. In these he brings forth new confirmations of his theories, and
reduces the phenomena of electro-magnetism to mathematical analysis.
Mr. Samuel Prime remarks (“Life of Morse,” 1875, p. 266) that the
discovery of the action of the spiral coil upon the magnetic needle
seems to have been independently made by Ampère in 1821:
“I showed that the current which is in the pile acts on the magnetic
needle by the conjunctive wire. I described the instrument, which I
proposed to construct, and, among others, the galvanic spiral. I read
a note upon the electro-chemical effects of a spiral of iron wire,
subjected to the action of the earth, directing an electric current
as well as a magnet. I announced the new fact of the attraction and
repulsion of two electric currents, without the intermediation of any
magnet, a fact which I had observed in conductors twisted spirally
(Tilloch’s _Journal of Science_, Vol. LVII. p. 47, 1821).
One of his biographers, Professor Chrystal says: “Scarcely had the
news of Oersted’s discovery reached France, when a French philosopher,
Ampère, set to work to develop the important consequences which it
involved. Physicists had long been looking for the connection between
magnetism and electricity, and had, perhaps, inclined to the view that
electricity was somehow to be explained as a magnetic phenomenon. It
was, in fact, under the influence of such ideas, that Oersted was led
to his discovery. Ampère showed that the explanation was to be found
in an opposite direction. He discovered the ponderomotive action of
one electric current on another, and, by a series of well-chosen
experiments, he established the elementary laws of electro-dynamic
action, starting from which, by a brilliant train of mathematical
analysis, he not only evolved the complete explanation of all the
electro-magnetic phenomena observed before him, but predicted many
hitherto unknown. The results of his researches may be summarized
in the statement that an electric current, in a linear circuit of
any form, is equivalent in its action, whether on magnets or other
circuits, to a magnetic shell bounded by the circuit, whose strength
at every point is constant and proportional to the strength of the
current. By his beautiful theory of molecular currents, he gave a
theoretical explanation of that connection between electricity and
magnetism which had been the dream of previous investigators. _If
we except the discovery of the laws of the induction of electric
currents_, made about ten years later by Faraday, _no advance in
the science of electricity can compare for completeness and brilliancy
with the work of Ampère_. Our admiration is equally great,
whether we contemplate the clearness and power of his mathematical
investigations, the aptness and skill of his experiments, or the
wonderful rapidity with which he elucidated his discovery when he had
once found the clew.”
“Oersted,” remarks M. Babinet, “was the Christopher Columbus of
magnetism; Ampère became its Pizarro and its Fernand Cortez.”
Of Ampère’s _astatic_ needles, a description, taken from one of
his memoirs (_Ann. de Ch. et de Ph._, Vol. XVIII. p. 320), appears
at pp. 280–281 of Fahie’s “History” (Knight’s “Mech. Dict.,” 1874, Vol.
I. p. 171, and Vol. II. p. 1181). For this greatly perfected form of
galvanometer the credit has erroneously been given to Prof. Cumming,
who first suggested the idea of neutralizing the directive force of
the needle arising from the earth’s magnetism, which he did by placing
a magnetized needle immediately beneath the movable or index needle.
Fahie adds, in a footnote: “In Prof. Cumming’s paper ‘On the Connection
of Galvanism and Magnetism,’ read before the Cambridge Philosophical
Society, April 2, 1821, he described a near approach to the astatic
needle. In order to neutralize the terrestrial magnetism he placed
a small magnetized needle under the galvanometer needle” (_Trans.
Cam. Phil. Soc._, Vol. I. p. 279). The credit of Ampère’s discovery
is sometimes given to Nobili, as in Noad’s “Manual of Electricity,”
London, 1859, p. 327; also Roget’s “Electro-Magnetism” in “Library of
Useful Knowledge,” London, 1832, p. 42.
As has been already shown (Laplace, A.D. 1820), the first proposal to
apply Oersted’s discovery to telegraphic purposes by substituting the
deflection of the magnetic needle through electric currents for the
divergence of the pith balls of the electroscope, was made by Ampère,
in his Memoir of Oct. 2, 1820, which appears in the _Comptes Rendus_,
and at p. 72, Vol. XV of the _Annales de Chimie et de Physique_. His
plan, remarks Sabine, was, however, doomed to the same fate as that of
Sömmering, of never coming into practice, and for the same reasons,
principally the number of line wires. Had Ampère combined his system,
or rather the one of Laplace, with that which Schweigger proposed of
reducing Sömmering’s telegraph to two wires, or with any other using a
code of signals, the problem of the electric telegraph would have been
solved from the year 1820. Ampère makes no mention of surrounding the
needles with _coils of wire_, as is so frequently stated by writers
on the telegraph. Indeed he could not then have even heard of the
galvanometer; for, although Schweigger’s paper on the subject was read
at Halle on the 16th of September 1820, it was not published until the
November following.
M. Jean Jacques Antoine Ampère (1800–1864), son of André Marie Ampère,
was an accomplished scholar who succeeded François Andrieux as
professor at the Collège de France and became a member of the French
Academy in 1847.
REFERENCES.--For accounts of Ampère’s rotary magnet,
electro-dynamic cylinders, revolving battery, and of his
electripeter employed to alter rapidly the direction of the
electric current in voltaic batteries, consult pp. 639, 640,
643, Vol. VIII of the eighth “Britannica.” Fahie, “Hist. of
El. Tel.,” p. 303. See “Catal. Sci. Papers Roy. Soc.,” Vol.
I. pp. 58, 61; Messrs. Sainte-Beuve et Littré’s account of
his life and labours in the _Revue des Deux Mondes_ for Feb.
15, 1837; “Notice sur M. Ampère,” _par_ M. E. Littré, Paris,
1843; Arago’s “Eulogy on Ampère,” translated, at pp. 111–171 of
the “Report of the Smithsonian Institution” for 1872. Consult
also “Report Smiths. Instit.” for 1857, pp. 100–107; Ampère’s
biography in the _Sci. Am. Suppl._, No. 674, p. 10760; also
Ampère’s “Journal et Correspondance,” Poggendorff, Vol. I. pp.
39, 40; Address of His Royal Highness the Duke of Sussex to
the Eng. Roy. Soc., 1836; Barlow on “Magnetic Attractions”:
_Comptes Rendus_ for 1838, Vol. VII. p. 81; _Bibl. Univ._,
XX; _Phil. Mag._, Vols. LVI. p. 308; LVII. pp. 40–47, “On the
Electro-Magnetic Experiments of Oersted and Ampère,” by Mr.
Hatchett, and pp. 47–49; _Ann. de Phys. de Bruxelles_, Vol.
VII; _Ann. de Ch. et de Phys._, XXIX; Du Moncel, Vol. III. p.
7; “Acad. de Paris,” Sept. 12, 1825; _La Lum. Elect._ for Oct.
31, 1891, p. 202; Roch, in “Zeitschr. f. Mathém.” 1859, p. 295;
Roget on Ampère’s theory of Mag.; K. W. Knochenhauer, _Pogg.
Annal._, XXXIV. p. 481; J. Marsh, “On a Particular Construction
of M. Ampère’s Rotating Cylinder,” _Phil. Mag._, LIX. p. 433,
1822; Henn, “De Amperi principiis ...”; “Memorial of Joseph
Henry,” 1880, pp. 59, 81; “Lib. of Use. Know.” (El. Mag.), pp.
24, 28, 83–92; Harris, “Rud. Elec.,” pp. 170, 171, and “Rud.
Mag.,” p. 130; Noad, “Manual,” pp. 661–662, 861–864; “Encycl.
Metrop.” (El. Mag.), Vol. IV. pp. 5–8; Highton, “Elec. Teleg.,”
p. 39; Gmelin’s “Chemistry,” Vol. I. p. 317; Mrs. Somerville,
“Conn. Phys. Sci.,” 1846, pp. 320, 321; Dr. Lardner, “Lectures,”
Vol. II. p. 125; J. F. W. Herschel, “Prelim. Dis. Nat. Phil.,”
1855, p. 243; Whewell, “Hist. Induc. Sc.,” 1859, Vol. II. pp.
242, 246, 619; “Ann. of Sc. Disc.” for 1850, p. 129, and for
1865, p. 125; “Smithsonian Report” for 1878, p. 273; Sturgeon,
“Sci. Researches,” Bury, 1850, pp. 12, 16, 29; _Jour. Frankl.
Inst._ for 1851, Vol. XXII. p. 59; Turnbull, “El. Mag. Tel.,”
1853, pp. 55 and 221; (Vail’s “History,” pp. 133, 134; Prof.
Henry’s Evid., 85a, record; Doct. Channing’s Ev., 47a, record;
Hibbard, Ev., 31_a_. ...) See also Humboldt’s “Cosmos,”
articles “Aurora Borealis,” “Volcanoes,” “Earthquakes”; Ampère
et Babinet, “Exposé des Nouv. Déc. ... de Oersted, Arago,
Ampère, Davy, Biot, Erman, Schweigger, De la Rive,” etc.,
Paris, 1822, translated into German “Darstellung der neuen ...
dem Französischen,” Leipzig, 1822, and alluded to in _Lumière
Electrique_ for July 18, 1891, pp. 148, 149; Hachette et
Ampère, “Sur les Expériences de Oersted et Ampère”: _Journal
de Physique_ for September 1820. _Annales de Chimie_ for 1825;
“Journal des Savants,” for June 1872; “Dict. Génér. de Biogr. et
d’Histoire,” Paris, 2^e ed., pp. 85–86; “Collection de Mémoires
relatifs à la Physique,” Paris 1885, 1887, Vols. II and III
_passim_, as per indexes; “Amer. Journ. of Psychology,” Vol. IV.
pp. 6–7.
For William Ritchie (1790–1837), the author of an able paper, “On
electro-magnetism, and Ampère’s proposal of telegraphic communication
by means of this power,” consult _Phil. Trans._ for 1833, p. 313;
“Abstracts of Papers ... Roy. Soc.,” Vol. II. pp. 350, 382; _Phil.
Mag._ or _Annals_, Vol. VII, 1830, p. 212; _Phil. Mag. and Journal of
Science_, Vol. III, 1833, pp. 37, 122, 124, 145.
For Leopoldo Nobili (1784–1835), frequently mentioned above, consult
“Bibl. Univ.,” Bruxelles, 1834 (Sc. et Arts), Tome LVI. pp. 82–89,
150–168; “Edin. Trans.” Vol. XII and _Phil. Mag._ Vol. XI, 1832, p.
359, for the account of experiments made by James David Forbes, similar
to those of Nobili, wherein an electric spark was elicited from a
natural magnet. For J. D. Forbes, see also _Phil. Mag._, 1832, Vol. XI.
p. 359. For Nobili and Antinori, consult _Phil. Mag._, Vol. XI, 1832,
pp. 401, 466; “Bibl. Britan.,” Vol. XXV, 1824, N.S. p. 38; Vol. XXIX,
1825, N.S. p. 119. For Antinori and Marchese Cosimo Ridolfi, consult
“Bibl. Britan.” Vol. XVI, N.S., 1821, pp. 72–75, 101–118.
For Prof. James Cumming (1777–1861), also frequently named in above
article, consult _Phil. Mag._, Vol. LX, 1822, p. 253; “Bibl.
Britan.,” Vol. XXV, N.S., 1824, p. 104, for experiments of Cumming,
Trail and Marsh; the investigations in the same line of Mr. Thos.
Stuart being especially reported on in “Bibl. Britan.,” Vol. XXVII,
N.S., 1824, pp. 199–206; “Dict. of Nat. Biog.,” Vol XIII. p. 296;
“Edin. Phil. Journal,” 1824, Vol. X. p. 185; “Cat. Sc. Papers Roy.
Soc.,” Vol. I. pp. 58–61; Vol. VI. p. 565; Vol. VII. p. 29; “Bibl.
Britan.,” Vol. XVI, N.S. p. 309; Vol. XVII, N.S. p. 16; Vol. XIX. p.
244; Vol. XX. pp. 173, 258; Vol. XXIV. p. 109.
For Le Chevalier Julius Konrad von Yelin (1771–1826), consult “Bibl.
Britan.,” Vol. XXIII, N.S., 1823, p. 38; Vol. XXIV, N.S., 1823,
p. 253, and, especially, the important tract on the discovery of
thermo-magnetism at p. 31 of his “Die Akademie der Wissenschaften und
ihre Gegner,” Munich, 1822.
=A.D. 1820.=--Arago (Dominique François Jean), famous French
astronomer, physicist and statesman (1786–1853), who at the early
age of twenty-three had, besides being Assistant Astronomer to the
Observatory, become the successor both of Lalande in the Academy of
Sciences and of Monge in the chair of analytical mathematics at the
Polytechnic School, and who, conjointly with Gay-Lussac, had founded
the highly valued _Annales de Chimie et de Physique_ in 1816,
communicates to the French Institute, on the 25th of September 1820,
his discovery that the electric current has the power of developing
magnetism in iron and steel. Into the axis of a galvanic conductor made
in the form of a coil, or helix, he placed a needle, the extremities
of the wire coil being connected to the poles of a battery, and
with this he proved that the wire not only acted on bodies already
magnetized, but that it could develop magnetism in such as did not
already possess the power. When soft iron was used, the magnetism
given was only temporary, but on repeating the experiment, M. Arago
succeeded completely in permanently magnetizing small steel needles.
Arago’s paper on the subject appears at p. 94, Vol. XV of the _Ann.
de Ch. et de Ph._, and it is said that at about the same time Dr.
Thos. J. Seebeck (1770–1831), and Georg Friedrich Pohl (1788–1849) laid
similar results before the Berlin Academy, also that Sir Humphry Davy
independently made a like discovery, of which he advised Dr. Wollaston,
Nov. 12, 1820. Reference to this fact has already been made at Davy,
under date A.D. 1801, wherein it was stated that the latter
had found iron filings to so adhere to the connecting wire as to form
a mass ten or twelve times the thickness of the wire. This was also
the case in the experiments of M. Arago, who, upon observing that the
filings rose before coming in contact with the conjugate wire, drew the
conclusion that each small piece of iron was converted into a temporary
magnet. Thus was Arago led to the discovery of what is called magnetic
induction by electric currents, or, in other words, that an electrical
current passing through a conductor will induce magnetic action in such
bodies near it as are capable of being magnetized (_Phil. Trans._
for 1821, p. 9; Tilloch’s _Jour. of Sci._, Vol. LVII. p. 42, 1821;
eighth “Britannica,” Vol. VIII. p. 532 and Vol. XIV. p. 640; Thomas
Thomson, “Outline of the Sciences,” p. 563).
A fact worth noting in connection with the development of Oersted’s
discovery by both Arago and Ampère, is that in order “to prevent the
communication of the electricity laterally in the folds of the coil,
the wire was insulated by varnish in the first instance and afterward
by winding silk or cotton around it” (F. C. Bakewell, “Elec. Sci.,”
London, 1853, p. 37).
On the 22nd of November 1824, Arago announced to the French Academy
of Sciences the remarkable discovery made by him of a new source of
magnetism in rotatory motion. He was led to this by observing that
when a magnetic needle was oscillating above or close by any body,
such as water or a plate of metal, it gradually oscillated in arcs of
less and less amplitude, as if it were standing in a resisting medium,
and, besides, that the oscillations performed in a given time were the
same in number (Humboldt’s “Cosmos,” “Magnetic Observations,” 1825).
He caused a circular copper plate to revolve immediately beneath a
magnetic needle or magnet, freely suspended so that the latter might
rotate in a plane parallel to that of the copper plate, and he found
that the needle tends to follow the circumvolution of the plate; that
it will deviate from its true direction, and that by increasing the
velocity of the plate the deviation will increase till the needle
passes the opposite point, when it will continue to revolve, and at
last with such rapidity that the eye will be unable to distinguish it.
This, says Mrs. Somerville, is quite independent of the motion of the
air, since it is the same if a pane of glass be interposed between the
magnet and the copper. When the magnet and the plate are at rest, not
the smallest effect, attractive, repulsive, or of any kind, can be
perceived between them. In describing this phenomenon Arago states that
it takes place not only with metals, but with all substances, although
the intensity depends upon the kind of substance in motion.
Arago’s experiments were repeated in London, March 7, 1825. His
valuable discovery, which obtained for him the Copley medal, and which
confirms the doctrine of the universal prevalence of magnetism in
all bodies, is recorded in Arago’s “Sur les Déviations ... aiguille
aimantée” (_An. de Ch. et de Ph._, Vol. XXXIII, and _Phil. Trans._,
p. 467 for 1825), and a solution of the phenomena is given by Faraday
in _Phil. Trans._ for 1832, p. 146, by Sir John Leslie in the Fifth
Dissertation of the eighth “Britannica,” p. 746, as well as in the
article “Magnetism” of the latter publication, and in Mrs. Somerville’s
“Conn. of Phys. Sc.,” pp. 325–327. (See also the observations recorded
in Humboldt’s “Cosmos,” 1849, Vol. I. pp. 172, 173; in Dr. Thomson’s
“Outline of the Sciences,” pp. 556–558; Fahie, pp. 282, 283, 321; Dr.
Whewell, Vol. II. pp. 254–256; Brewster’s _Edin. Jour. of Sci._, 1826,
Vol. III. p. 179; “Dict. Gén. de Biogr. et d’Histoire,” Paris, 2^e ed.
p. 126.)
In Brewster’s _Edinburgh Journal of Science_ (Vol. V. p. 325), notice
is given of Arago’s then recent researches on the influence which
bodies considered not magnetic have on the motions of the magnetic
needle, and reference is made to a new communication transmitted
by Arago to the Académie des Sciences, as well as to a report of
additional experiments in the same line given at meetings held July
3 and 10, 1826. Arago satisfactorily meets the denials made by
Leopoldo Nobili and another Italian natural philosopher (Liberato
Giovanni Bacelli) that substances not metallic have any influence
on the magnetic oscillations, and he announces as a result of his
investigations that, for certain positions of a vertical needle, and
for velocities of rotation sufficiently rapid, the repulsive force
which is exerted in the direction of the radius is as great as the
force perpendicular to the radius, of which the effects are observed
upon a horizontal needle.
Poisson having stated in his memoir “On the Theory of Magnetism” in
motion (see Poisson at A.D. 1811) that Coulomb had recognized
the magnetic virtue in all bodies, independently of the iron which
they contain, Arago remarked that the idea of Coulomb was quite
different from his, Coulomb having been of opinion that a quantity of
iron, although too small for chemical analysis even to appreciate, was
sufficient to produce in bodies which contained it appreciable magnetic
effects. MM. Thénard and La Place confirmed this remark. Brewster adds
that, in justice to Coulomb, it is necessary to state that he is the
undoubted author of the discovery that _all bodies, whether organic
or inorganic, are sensible to the influence of magnetism_. M. Biot
has remarked that there are two ways of explaining this, _either all
substances in nature are susceptible of magnetism, or they all contain
portions of iron, or other magnetic metals, which communicate to them
this property_. This last explanation, though adopted by Coulomb, by
no means affects his claim to the discovery of the general fact that
all bodies, whether organic or inorganic, are susceptible of becoming
magnetic. Prof. Hansteen has drawn from numerous experiments and
observations the important conclusion that _every vertical object, of
whatever material it is composed, has a magnetic south pole above, and
a north pole below_ (_Edin. Phil. Journal_ for January-April
1821).
M. Arago made many valuable investigations concerning the influence of
the aurora borealis on the needle, on the variations of the latter,
upon the nature of meteors, lightning, the zodiacal light, magnetic
storms, etc. etc., which are admirably recorded more particularly in
the great work of Alex. von Humboldt. The latter remarks that Arago has
left behind him a treasury of magnetical observations (upward of 52,600
in number) carried on from 1818 to 1835, which have been carefully
edited by M. Fédor Thoman, and published in the “Œuvres Complètes de
François Arago” (Vol. IV. p. 493). Much could be said, especially
regarding Arago’s paper, presented by him to the Academy of Sciences
in 1811, which is considered to have established the foundation of
chromatic polarization. Mention must at any rate be made of the fact
that in Humboldt’s estimation the discovery of the two kinds of
polarization of light may be considered the most brilliant of the
century. They, unquestionably, rank among the most splendid of optical
phenomena.
Etienne Louis Malus, a distinguished French philosopher (Fifth Dissert.
of “Encycl. Brit.”), discovered in 1808 polarization by reflection
from polished surfaces, and Arago, during 1811, made the discovery of
coloured polarization. A world of wonder, remarks Humboldt, composed
of manifold modified waves of light having new properties was now
revealed. A ray of light which reaches our eyes, after traversing
millions of miles from the remotest regions of heaven, announces
of itself in Arago’s polariscope (consisting of a plate of quartz
cut across the axis placed in one end of a tube, at the other end
of which is a doubly refracting prism) whether it is reflected or
refracted, whether it emanates from a solid or fluid, or gaseous body,
even announcing the degree of its intensity (Delambre, “Histoire de
l’Astronomie,” p. 652; Humboldt, “Cosmos,” 1849, Vol. I. p. 33; Vol.
II. p. 715).
In 1818, Arago was elected a F.R.S.; he became a member of the Royal
Astronomical Society and also member of the Bureau des Longitudes
during 1822, was made Perpetual Secretary of the Academy and Director
of the Paris Observatory eight years later, and received the Rumford
medal in 1850. The Copley medal given him in 1825 had never before been
conferred upon a Frenchman of science. It was upon his urgent request
that the “Annuaire du Bureau des Longitudes” and “Les Comptes Rendus
hebdomadaires” were commenced by the Academy, 1828–1835.
In a letter to Schumacher, Humboldt speaks of Arago as “one gifted with
the noblest of natures, equally distinguished for intellectual power
and for moral excellence.” In conjunction with Gay-Lussac, Arago was,
for almost half a century, Humboldt’s most intimate friend, and their
ever-increasing intimacy became such as to lead to a perfect unity of
thought on scientific subjects. It cannot, therefore, be considered an
exaggerated expression of feeling when, in a letter to Geoffroy St.
Hilaire, dated Berlin, June 24, 1829, Humboldt should conclude with the
words: “Pray remember me to MM. Valenciennes, Deleuze and Cuvier, but
especially to him whom I hold dearest in this life, to M. Arago.”
REFERENCES.--Poggendorff, Vol. I. pp. 53, 54, and the several
biographies named at p. 202, Vol. I of “Johnson’s New Univ.
Cycl.,” 1877; J. A. Barral, “Œuvres de F. Arago,” 1854–1855;
Faria E. De e Arago, “Breve compendio ...” Lisbon, 1800; Arago’s
“Notices Scientifiques,” “Cat. Sc. Papers Roy. Soc.,” Vol. I.
pp. 80–84; Vol. IV. pp. 697–701; Vol. VI. pp. 567, 736–737;
Vol. VIII. p. 537; “Encycl. Metropol.,” Vol IV (Magnetism),
pp. 6, 7; J. F. W. Herschel, “Nat. Phil.,” 1855, pp. 117, 244,
and his account of the repetition of M. Arago’s experiments on
rotatory magnetism in _Phil. Trans._ for 1825; Whewell, “Hist.
Induc. Sci.,” 1859, Vol. II. p. 226; _Phil. Mag._, Vols. LIX.
p. 233; LVII. pp. 40–49; LVIII. p. 50; LXI, p. 134; “Lib.
Useful Knowledge’” (Magnetism), p. 91; Noad, “Manual,” pp.
204, 534; “Ann. of Sci. Disc.” for 1850, p. 124; Harris, “Rud.
Magn.,” Parts I, II. pp. 58–61 and _Phil. Trans._ for 1831,
Part I; Prime’s “Life of Morse,” pp. 168, 265, 266; Gmelin’s
“Chemistry,” Vol. I. p. 317; _Comptes Rendus_ for 1836, Vol. II.
p. 212; Dredge, “Electr. Illum.,” Vol. II. p. 122; Sturgeon,
“Scient. Res.,” Bury, 1850, pp. 13, 37, 216, etc.; Appleton,
“New Am. Cycl.,” Vol. XI. p. 71; _Sci. Am. Suppl._, No. 204, p.
3254; _La Lumière Electrique_ for Oct. 31, p. 202; “Reports of
the Smithsonian Institution” for 1857, pp. 102, 107; for 1862,
pp. 132–143, and p. 127 of last named for Malus’ discovery.
Houzeau et Lancaster, “Bibl. Générale,” Vol. I. part. i. pp.
676–677 detailing the contents of Arago’s “Œuvres Complètes,”
published in thirteen volumes under the direction of J. A.
Barral, also Vol. II. p. 76; _Cornhill Magazine_, Vol. XVII. p.
727; Pierre Prévost, “Tentative,” Genève, 1822 (Poggendorff,
Vol. II. p. 525); _Phil. Mag._, Vol. LVIII. p. 50; Vol. LXI. p.
134; “Abstracts of Papers ... Roy. Soc.,” Vol. II. p. 249.
=A.D. 1821.=--Ridolfi (Marquis Cosimo di), an Italian agriculturist,
is the author of several treatises on _fenomeni elettro-magnetici_,
published in Florence, wherein he expresses the belief that “because
electricity produces both magnetic and calorific phenomena, the
elements giving these separately may possibly be so compounded together
as to produce electricity; which infers that electricity is a compound
of magnetism and caloric.”
REFERENCES.--“Antologia di Firenze,” 1824, p. 159, and “Biblio.
Ital.,” Vol. LXIII. p. 268 for Ridolfi’s description of the
electric plate machine of Novellucci; also “Annales de Chimie et
de Physique,” Vol. X. p. 287; Sturgeon, “Scientific Researches,”
1850, Sec. I. p. 29; “Bibliothèque Universelle” for Feb. 1821.
=A.D. 1821.=--Scoresby (Dr. William) (1789–1857), English
master-mariner, and author of numerous scientific and other treatises,
first publishes, in the “Trans. of the Edinburgh Society,” accounts
of his magnetometer--magnetimeter--and of his electro-magnetic
experiments. These were duly followed up by full reports of his
many interesting investigations relative, more particularly, to the
development of magnetic properties of metals by percussion, as well as
to magnetic induction, and regarding the uniform permeability of all
known substances to the magnet’s influence.
REFERENCES.--“Abstracts of Papers ... Roy. Soc.,” London
1832–1833, Vol. II. pp. 108, 168, 210; “Dict. of Nat. Biog.,”
London, 1897, Vol. LI. p. 6; _Phil. Trans._ for 1822–1824;
“Trans. Edin. Soc.,” Vol. IX. pp. 243–258, 353, 465; Vol. XI
for 1824; Vol. XII for 1831; Vol. XIII for 1832, and Vol.
XIV for 1833; “Brewster’s Jour. of Sc.,” Vol. VIII for 1828;
“Bibliothèque Britannique,” Genève, 1796, N.S., Vol. XXIX for
1825, p. 185; “Edin. Phil. Jour.” for 1823, Vol. IX. p. 45.
=A.D. 1821.=--Babinet (Jacques) (1794–1872), French scientist, is
the author of a very valuable treatise, published in Paris, upon the
magnetical discoveries of Oersted, Ampère, Arago, Davy and others. This
was followed by his “Résumé complet de la physique,” etc., and by a
companion work treating of the relations of ponderable and imponderable
bodies to the phenomena of magnetism and electricity, also, during
the year 1829, by his Memoir upon the determination of terrestrial
magnetism.
He succeeded Savary as Professor at the Collège de France in 1838, and,
two years later, took the place of Dulong in the section of General
Physics at the Académie des Sciences, becoming not long after the
Assistant Astronomer at the Paris Observatory for Meteorology.
His numerous scientific treatises are to be found throughout the
“Mémoires de la Société Philomathique,” the “Annales de Physique,”
the “Comptes Rendus,” the “Revue des Deux-Mondes” and other prominent
publications of the day.
REFERENCES.--Larousse, “Dict. Univ.,” Vol. II. p. 10; “Eng.
Cycl.,” London, 1872, Supplement, p. 143; “Biog. Gén.,” Vol.
IV. p. 21; Mme. Blavatsky, “Isis Unveiled,” Vol. I. p. 202; and
Ronalds’ “Catalogue,” pp. 10–11, for the joint works of Ampère
and Babinet.
=A.D. 1821.=--Pfaff (Christian Heinrich) (1773–1852), who became
Professor of Medicine, Physics, etc., at the Kiel University, and
was one of the most energetic followers of Volta, sends an unusually
interesting communication to Gilbert’s “Annalen der Physik” and to
Schweigger’s “Journal für Chemie und Physik,” wherein he very ably
supports the views of the Pavia physicist.
Pfaff had, long before that, become favourably known through numerous
scientific papers, which were translated into the leading foreign
journals, the ones entitled “Dissertatio inauguralis ...” published at
Stuttgart, and “Über thierische Elektricität,” published at Leipzig,
having brought him special distinction. He had also written, more
particularly, upon the experiments made by Alex. von Humboldt as well
as relative to Pacchiani’s “Formation of Muriatic Acid by Galvanism,”
alluded to at the A.D. 1805 entry, and it was by reason of the
investigations made by Pfaff and Van Marum that the use of the voltaic
column was generally abandoned. These scientists had constructed very
strong piles consisting, in some instances, of as many as seventy large
separate discs, when they found that the lower layers of wet cloth or
of pasteboard were so seriously compressed by the discs above them as
to neutralize their effect.
REFERENCES.--Johann Samuel T. Gehler’s “Phys. Wörterbuch,” Vol.
VI. pp. 507, 517–518; “Roy. Soc. Cat. Sc. Papers,” Vol. IV. pp.
866–871; “Ann. der Chemie,” Vol. XXXIV. p. 307; Vol. LX. p.
314; “Annales de Chimie et de Physique,” Vol. XLI. pp. 236–247;
Sturgeon, “Annals,” Vol. VIII. pp. 80, 146; Noad, “Manual,” p.
558; Wilkinson, “Elements,” Vol. I. pp. 1–8, 18, 22, 196, 326,
407; Vol. II. p. 106; “Encycl. Brit.” ninth ed., Vol. XVIII. p.
725; “Soc. Philom.,” Vol. II. p. 181; _Phil. Mag._, Vol. XXVII.
p. 338.
=A.D. 1821.=--Faraday (Michael), a very distinguished English
chemist and natural philosopher (1791–1867), who probably did
more for the development of the study of electrical science than
any other investigator, publishes his “History of the Progress of
Electro-Magnetism” and succeeds, on the morning of Christmas (December
25), 1821, both in causing a magnetic needle to rotate round a wire
carrying an electric current and in making the wire rotate around the
needle, thus rendering possible the production of continuous mechanical
motion by electricity.
The apparatus with which he produced this result is described in nearly
all works treating of natural philosophy. Premising his reference to
this discovery of Mr. Faraday, whose original papers thereon appear
in the _Quarterly Journal of Sciences and the Arts_, Vol. XII.
pp. 75, 186, 283 and 416 (the first bearing date September 11, 1821),
Dr. Whewell says that on attempting to analyze the electro-magnetic
phenomena observed by Oersted and others into their simplest forms,
they appeared, at least at first sight, to be different from any
mechanical actions which had yet been observed. It seemed as if the
conducting wire exerted on the pole of the magnet a force which was not
attractive or repulsive, but _transverse_; not tending to draw the
point acted on nearer, or to push it further off, in the line which
reached from the acting point, but urging it to move at right angles
to this line. The forces appeared to be such as Kepler had dreamt of
in the infancy of mechanical conceptions, rather than such as those of
which Newton had established the presence in the solar system, and such
as he, and all his successors, had supposed to be the only kinds of
force which exist in nature. The north pole of the needle moved as if
it were impelled by a vortex revolving round the wire in one direction,
while the south pole seemed to be driven by an opposite vortex (called
by Wollaston _vertiginous magnetism_ and considered by Mr. Barlow
as the result of _tangential action_). The case seemed novel, and
almost paradoxical. It was soon established by experiments, made in a
great variety of forms, that the mechanical action was really of this
transverse kind. And a curious result was obtained, which a little
while before would have been considered as altogether incredible: that
this force would cause a constant and rapid revolution of either of the
bodies about the other--of the conducting wire about the magnet, or of
the magnet about the conducting wire (Vol. XII of the “Journal of the
Royal Institution”; Watkins, “Popular Sketch of Electro-Magnetism; or
Electro-Dynamics,” London, 1828; Mrs. Somerville, “Connection of Phys.
Sciences,” 1846, p. 315).
Passing over many of Faraday’s important scientific investigations
in other lines, we come to his second great discovery, that of
_magneto-electric induction_, which is the converse of Oersted’s
(developed by Ampère and Arago), the production of electricity by
magnetism. This is recorded in the first series of “Experimental
Researches in Electricity,” read November 24, 1831 before the Royal
Society, of which body Faraday had become a Fellow during 1824, and it
is published at p. 125 of the _Phil. Trans._ for 1832.