[1] From a photograph, with figures, to show the relative size of the
tube aperture.
[2] Weld’s _History of the Royal Society_, vol. ii. p. 188.
[3] Dr. Whewell (_Bridgewater Treatise_, p. 266) well observes, that
Boyle and Pascal are to hydrostatics what Galileo is to mechanics, and
Copernicus, Kepler, and Newton are to astronomy.
[4] The Rev. Mr. Turnor recollects that Mr. Jones, the tutor,
mentioned, in one of his lectures on optics, that the reflecting
telescope belonging to Newton was then lodged in the observatory over
the gateway; and Mr. Turnor thinks that he once saw it, with a finder
affixed to it.
[5] The story of the dog “Diamond” having caused the burning of
certain papers is laid in London, and in Newton’s later years. In the
notes to Maude’s _Wenleysdale_, a person then living (1780) relates,
that Sir Isaac being called out of his study to a contiguous room, a
little dog, called Diamond, the constant but incurious attendant of
his master’s researches, happened to be left among the papers, and
by a fatality not to be retrieved, as it was in the latter part of
Sir Isaac’s days, threw down a lighted candle, which consumed the
almost finished labour of some years. Sir Isaac returning too late
but to behold the dreadful wreck, rebuked the author of it with an
exclamation (_ad sidera palmas_), “O Diamond! Diamond! thou little
knowest the mischief done!” without adding a single stripe. M. Biot
gives this fiction as a true story, which happened some years after
the publication of the _Principia_; and he characterises the accident
as having deprived the sciences forever of the fruit of so much of
Newton’s labours.--Brewster’s _Life_, vol. ii. p. 139, note. Dr. Newton
remarks, that Sir Isaac never had any communion with dogs or cats; and
Sir David Brewster adds, that the view which M. Biot has taken of the
idle story of the dog Diamond, charged with fire-raising among Newton’s
manuscripts, and of the influence of this accident upon the mind of
their author, is utterly incomprehensible. The fiction, however, was
turned to account in giving colour to M. Biot’s misrepresentation.
[6] Bohn’s edition.
[7] When at Pisa, many years since, Captain Basil Hall investigated
the origin and divergence of the tower from the perpendicular, and
established completely to his own satisfaction that it had been built
from top to bottom originally just as it now stands. His reasons for
thinking so were, that the line of the tower, on that side towards
which it leans, has not the same curvature as the line on the opposite,
or what may be called the upper side. If the tower had been built
upright, and then been made to incline over, the line of the wall on
that side towards which the inclination was given would be more or less
concave in that direction, owing to the nodding or “swagging over” of
the top, by the simple action of gravity acting on a very tall mass
of masonry, which is more or less elastic when placed in a sloping
position. But the contrary is the fact; for the line of wall on the
side towards which the tower leans is decidedly more convex than the
opposite side. Captain Hall had therefore no doubt whatever that the
architect, in rearing his successive courses of stones, gained or
stole a little at each layer, so as to render his work less and less
overhanging as he went up; and thus, without betraying what he was
about, really gained stability.--See _Patchwork_.
[8] Lord Bacon proposed that, in order to determine whether the gravity
of the earth arises from the gravity of its parts, a clock-pendulum
should be swung in a mine, as was recently done at Harton colliery by
the Astronomer-Royal.
When, in 1812, Ampère noted the phenomena of the pendulum, and showed
that its movement was produced only when the eye of the observer was
fixed on the instrument, and endeavoured to prove thereby that the
motion was due to a play of the muscles, some members of the French
Academy objected to the consideration of a subject connected to such an
extent with superstition.
[9] This curious fact was first recorded by Pepys, in his _Diary_,
under the date 31st of July 1665.
[10] The result of these experiments for ascertaining the variation
of the gravity at great depths, has proved beyond doubt that the
attraction of gravitation is increased at the depth of 1250 feet by
1/19000 part.
[11] See the account of Mr. Baily’s researches (with two illustrations)
in _Things not generally Known_, p. vii., and “Weight of the Earth,” p.
16.
[12] Fizeau gives his result in leagues, reckoning twenty-five to the
equatorial degree. He estimates the velocity of light at 70,000 such
leagues, or about 210,000 miles in the second.
[13] See _Things not generally Known_, p. 88.
[14] Some time before the first announcement of the discovery of
sun-painting, the following extract from Sir John Herschel’s _Treatise
on Light_, in the _Encyclopædia Metropolitana_, appeared in a popular
work entitled _Parlour Magic_: “Strain a piece of paper or linen upon
a wooden frame, and sponge it over with a solution of nitrate of
silver in water; place it behind a painting upon glass, or a stained
window-pane, and the light, traversing the painting or figures, will
produce a copy of it upon the prepared paper or linen; those parts in
which the rays were least intercepted being the shadows of the picture.”
[15] In his book on Colours, Mr. Doyle informs us that divers, if not
all, essential oils, as also spirits of wine, when shaken, “have a
good store of bubbles, which appear adorned with various and lively
colours.” He mentions also that bubbles of soap and turpentine exhibit
the same colours, which “vary according to the incidence of the sight
and the position of the eye;” and he had seen a glass-blower blow
bubbles of glass which burst, and displayed “the varying colours of the
rainbow, which were exceedingly vivid.”
[16] The original idea is even attributed to Copernicus. M. Blundevile,
in his _Treatise on Cosmography_, 1594, has the following passage,
perhaps the most distinct recognition of authority in our language:
“How prooue (prove) you that there is but one world? By the authoritie
of Aristotle, who saieth that if there were any other world out of
this, then the earth of that world would mooue (move) towards the
centre of this world,” &c.
Sir Isaac Newton, in a conversation with Conduitt, said he took “all
the planets to be composed of the same matter with the earth, viz.
earth, water, and stone, but variously concocted.”
[17] Sir William Herschel ascertained that our solar system is
advancing towards the constellation Hercules, or more accurately to a
point in space whose right ascension is 245° 52′ 30″, and north polar
distance 40° 22′; and that the quantity of this motion is such, that to
an astronomer placed in Sirius, our sun would appear to describe an arc
of little more than _a second_ every year.--_North-British Review_, No.
3.
[18] See M. Arago’s researches upon this interesting subject, in
_Things not generally Known_, p. 4.
[19] This eloquent advocacy of the doctrine of “More Worlds than One”
(referred to at p. 51) is from the author’s valuable _Outlines of
Astronomy_.
[20] Professor Challis, of the Cambridge Observatory, directing the
Northumberland telescope of that institution to the place assigned by
Mr. Adams’s calculations and its vicinity on the 4th and 12th of August
1846, saw the planet on both those days, and noted its place (among
those of other stars) for re-observation. He, however, postponed the
_comparison_ of the places observed, and not possessing Dr. Bremiker’s
chart (which would at once have indicated the presence of an unmapped
star), remained in ignorance of the planet’s existence as a visible
object till the announcement of such by Dr. Galle.
[21] For several interesting details of Comets, see “Destruction of the
World by a Comet,” in _Popular Errors Explained and Illustrated_, new
edit. pp. 165-168.
[22] The letters of Sir Isaac Newton to Dr. Bentley, containing
suggestions for the Boyle Lectures, possess a peculiar interest in the
present day. “They show” (says Sir David Brewster) “that the _nebular
hypothesis_, the dull and dangerous heresy of the age, is incompatible
with the established laws of the material universe, and that an
omnipotent arm was required to give the planets their positions and
motions in space, and a presiding intelligence to assign to them the
different functions they had to perform.”--_Life of Newton_, vol. ii.
[23] The constitution of the nebulæ in the constellation of Orion has
been resolved by this instrument; and by its aid the stars of which it
is composed burst upon the sight of man for the first time.
[24] Several specimens of Meteoric Iron are to be seen in the
Mineralogical Collection in the British Museum.
[25] _Life of Sir Isaac Newton_, vol. i. p. 62.
[26] _Description of the Monster Telescope_, by Thomas Woods, M.D. 4th
edit. 1851.
[27] This instrument also discovered a multitude of new objects in the
moon; as a mountainous tract near Ptolemy, every ridge of which is
dotted with extremely minute craters, and two black parallel stripes in
the bottom of Aristarchus. Dr. Robinson, in his address to the British
Association in 1843, stated that in this telescope a building the size
of the Court-house at Cork would be easily visible on the lunar surface.
[28] Mr. Hopkins supports his Glacial Theory by regarding the _Waves
of Translation_, investigated by Mr. Scott Russell, as furnishing
a sufficient moving power for the transportation of large rounded
boulders, and the formation of drifted gravel. When these waves of
translation are produced by the sudden elevation of the surface of
the sea, the whole mass of water from the surface to the bottom of
the ocean moves onward, and becomes a mechanical agent of enormous
power. Following up this view, Mr. Hopkins has shown that “elevations
of continental masses of only 50 feet each, and from beneath an ocean
having a depth of between 300 and 400 feet, would cause the most
powerful divergent waves, which could transport large boulders to great
distances.”
[29] It is scarcely too much to say, that from the collection of
specimens of building-stones made upon this occasion, and first
deposited in a house in Craig’s Court, Charing Cross, originated,
upon the suggestion of Sir Henry Delabeche, the magnificent Museum of
Practical Geology in Jermyn Street; one of the most eminently practical
institutions of this scientific age.
[30] Mr. R. Mallet, F.R.S., and his son Dr. Mallet, have constructed a
seismographic map of the world, with seismic bands in their position
and relative intensity; and small black discs to denote volcanoes,
femaroles, and soltataras, and shades indicating the areas of
subsidence.
[31] It has been computed that the shock of this earthquake pervaded
an area of 700,000 miles, or the twelfth part of the circumference of
the globe. This dreadful shock lasted only five minutes; and nearly
the whole of the population being within the churches (on the feast of
All Saints), no less than 30,000 persons perished by the fall of these
edifices.--See _Daubeny on Volcanoes_; _Translator’s note, Humboldt’s
Cosmos_.
[32] Mr. Murray mentions, on the authority of the Rev. Dr. Robinson,
of the Observatory at Armagh, that a rough diamond with a red tint,
and valued by Mr. Rundell at twenty guineas, was found in Ireland,
many years since, in the bed of a brook flowing through the county of
Fermanagh.
[33] The use of malachite in ornamental work is very extensive in
Russia. Thus, to the Great Exhibition of 1851 were sent a pair of
folding-doors veneered with malachite, 13 feet high, valued at
6000_l._; malachite cases and pedestals from 1500_l._ to 3000_l._
a-piece, malachite tables 400_l._, and chairs 150_l._ each.
[34] Longfellow has written some pleasing lines on “The Fiftieth
Birthday of M. Agassiz. May 28, 1857,” appended to “The Courtship of
Miles Standish,” 1858.
[35] The _sloth_ only deserves its name when it is obliged to attempt
to proceed along the ground; when it has any thing which it can lay
hold of it is agile enough.
[36] Dr. A. Thomson has communicated to _Jameson’s Journal_, No. 112,
a Description of the Caves in the North Island, with some general
observations on this genus of birds. He concludes them to have been
indolent, dull, and stupid; to have lived chiefly on vegetable food in
mountain fastnesses and secluded caverns.
In the picture-gallery at Drayton Manor, the seat of Sir Robert Peel,
hangs a portrait of Professor Owen, and in his hand is depicted the
tibia of a Moa.
[37] According to the law of correlation, so much insisted on by
Cuvier, a superior character implies the existence of its inferiors,
and that too in definite proportions and constant connections; so
that we need only the assurance of one character, to be able to
reconstruct the whole animal. The triumph of this system is seen in
the reconstruction of extinct animals, as in the above case of the
Dinornis, accomplished by Professor Owen.
[38] Not only at London, but at Paris, Vienna, Berlin, Turin. St.
Petersburg, and almost every other capital in Europe; at Liege, Caen,
Montpellier, Toulouse, and several other large towns,--wherever,
in fact, there are not great local obstacles,--the tendency of the
wealthier inhabitants to group themselves to the west is as strongly
marked as in the British metropolis. At Pompeii, and other ancient
towns, the same thing maybe noticed; and where the local configuration
of the town necessitates an increase in a different direction, the
moment the obstacle ceases houses spread towards the west.
[39] By far the most complete set of experiments on the Radiation
of Heat from the Earth’s Surface at Night which have been published
since Dr. Wells’s Memoir _On Dew_, are those of Mr. Glaisher, F.R.S.,
_Philos. Trans._ for 1847.
[40] The author is largely indebted for the illustrations in this new
field of research to Lieutenant Maury’s valuable work, _The Physical
Geography of the Sea_. Sixth edition. Harper, New York; Low, Son, and
Co., London.
[41] It is the chloride of magnesia which gives that damp sticky
feeling to the clothes of sailors that are washed or wetted with salt
water.
[42] This fraction rests on the assumption that the dilatation of the
substances of which the earth is composed is equal to that of glass,
that is to say, 1/18000 for 1°. Regarding this hypothesis, see Arago,
in the _Annuaire_ for 1834, pp. 177-190.
[43] Electricity, traversing excessively rarefied air or vapours,
gives out light, and doubtless also heat. May not a continual current
of electric matter be constantly circulating in the sun’s immediate
neighbourhood, or traversing the planetary spaces, and exerting in the
upper regions of its atmosphere those phenomena of which, on however
diminutive a scale, we have yet an unequivocal manifestation in our
Aurora Borealis?
[44] Could we by mechanical pressure force water into a solid state, an
immense quantity of heat would be set free.
[45] See Mr. Hunt’s popular work, _The Poetry of Science; or, Studies
of Physical Phenomena of Nature_. Third edition, revised and enlarged.
Bohn, 1854.
[46] Canton was the first who in England verified Dr. Franklin’s idea
of the similarity of lightning and the electric fluid, July 1752.
[47] This is mentioned in _Procli Diadochi Paraphrasis Ptolem._, 1635.
(Delambre, _Hist. de l’Astronomie ancienne_.)
[48] The first Variation-Compass was constructed, before 1525, by an
ingenious apothecary of Seville, Felisse Guillen. So earnest were
the endeavours to learn more exactly the direction of the curves of
magnetic declination, that in 1585 Juan Jayme sailed with Francisco
Gali from Manilla to Acapulco, for the sole purpose of trying in the
Pacific a declination instrument which he had invented.--_Humboldt._
[49] Gilbert was surgeon to Queen Elizabeth and James I., and died
in 1603. Whewell justly assigns him an important place among the
“practical reformers of the physical sciences.” He adopted the
Copernican doctrine, which Lord Bacon’s inferior aptitude for physical
research led him to reject.
[50] This illustration, it will be seen, does not literally correspond
with the details which precede it.
[51] Mr. Crosse gave to the meeting a general invitation to Fyne Court;
one of the first to accept which was Sir Richard Phillips, who, on
his return to Brighton, described in a very attractive manner, at the
Sussex Institution, Mr. Crosse’s experiments and apparatus; a report of
which being communicated to the _Brighton Herald_, was quoted in the
_Literary Gazette_, and thence copied generally into the newspapers of
the day.
[52] These experiments were performed at the expense of the Royal
Society, and cost 10_l._ 5_s._ 6_d._ In the Paper detailing the
experiments, printed in the 45th volume of the _Philosophical
Transactions_, occurs the first mention of Dr. Franklin’s name, and of
his theory of positive and negative electricity.--_Weld’s Hist. Royal
Soc._ vol. i. p. 467.
[53] In this year Andrew Crosse said: “I prophesy that by means of
the electric agency we shall be enabled to communicate our thoughts
instantaneously with the uttermost parts of the earth.”
[54] To which paper the writer is indebted for many of these details.
[55] These illustrations have been in the main selected and abridged
from papers in the _Companion to the Almanac_, 1858, and the _Penny
Cyclopædia_, 2d supp.
[56] Newton was, however, much pestered with inquirers; and a
Correspondent of the _Gentleman’s Magazine_, in 1784, relates that he
once had a transient view of a Ms. in Pope’s handwriting, in which
he read a verified anecdote relating to the above period. Sir Isaac
being often interrupted by ignorant pretenders to the discovery of
the longitude, ordered his porter to inquire of every stranger who
desired admission whether he came about the longitude, and to exclude
such as answered in the affirmative. Two lines in Pope’s Ms., as the
Correspondent recollects, ran thus:
“‘Is it about the longitude you come?’
The porter asks: ‘Sir Isaac’s not at home.’”
[57] In trying the merits of Harrison’s chronometers, Dr. Maskelyne
acquired that knowledge of the wants of nautical astronomy which
afterwards led to the formation of the Nautical Almanac.
[58] A slight electric shock is given to a man at a certain portion of
the skin; and he is directed the moment he feels the stroke to make a
certain motion, as quickly as he possibly can, with the hands or with
the teeth, by which the time-measuring current is interrupted.
[59] Through the calculations of M. Le Verrier.