from the glass whilst in a state of fusion, by means of this wheel; to
this they think those words of Martial refer, where he says, _calices
audaces_, having reference to the boldness of the artisan’s touch;
those vessels he was constructing often broke under the last touch he
bestowed upon his transparent labours, although, perhaps, of costly
value; these accidents must of necessity have rendered those articles
extremely expensive.
There are not wanting many who affirm the art of glass-cutting,
with the instruments necessary for that operation, to be of modern
invention. Those assign it to the ingenuity of Caspar Lehmann,
originally an engraver on iron and steel, and who, as Beckmann
informs us, made an attempt, which succeeded, in cutting crystal, and
afterwards glass in the same manner. This artist, we are told, was in
the service of Rodolphus, the second emperor of that name, who, in
the year 1609, besides giving him valuable presents, conferred on him
the title of lapidary and glass-cutter to his court, and gave him a
patent, allowing him the exclusive privilege of exercising this new
art. He worked at Prague, where he had an assistant of the name of
Zacharias Belzer; but George Schwanhard, one of his pupils, carried
on the business to a much larger extent. The last named was a son of
Hans Schwanhard, a joiner at Rothenburg, and was born in 1601; at the
age of seventeen he went to Prague, to learn the art of cutting glass
from Lehmann. His good behaviour won so much upon the affections of
his master, that on his death in the year 1622, he left him his heir.
Schwanhard succeeded in obtaining a continuation of the patent from
the emperor, and removed to Nuremburg, where he wrought for many of
the nobility of that district. This was, we believe, the occasion of
that city claiming the honour of being the birth-place of this new
art. In the year 1652, he worked at Prague, and also at Ratisbon, by
command of the Emperor Ferdinand III.; and he died in 1676. He left
two sons, who both followed the lucrative employment of their father.
Afterwards Nuremburg produced many expert masters in the art, who,
from the improvement in the tools, and also from discovering more
economical modes of using them, were enabled to execute the orders of
the public at a more moderate rate than had been previously charged
for some articles. Those latter masters likewise brought this art to a
much greater degree of perfection. Notwithstanding Zahn was of the same
country, and must have been apprised of the facts previously stated,
yet he mentions it as a very recent invention at Nuremberg, at the time
he published his “Oculus Artificial.” He also furnishes a plate, giving
at the same time a description of the various instruments employed.
However, that this invention is not purely _novel_, may be perceived
from those facts we have already submitted.
It should be stated that before this latter re-introduction, artists
used, with a diamond, to cut figures upon glass in almost every form,
as far as the representation by lines went. The history of diamonds has
been presented to the public by Mr. Mawe, in his observations on the
diamond districts of Brazil. It appears to be yet undetermined whether
the ancients used that stone for the purpose of cutting others; upon
this point Pliny appears to be satisfied that they did.
Solinus and Isidore both express themselves in a manner the reverse.
But although this may leave us in some doubt, it appears pretty clear
that they did not attempt to cut that valuable production with its
own dust, or to give it different faces, or render it more brilliant
by the same means. If this point was settled, there could be no great
difficulty in affirming or negativing the fact of their engraving upon
that stone. Thus doubts appear to increase on this head, for Mariette
denies that they did; Natter appears uncertain; and Klotz asserts
with confidence it was certain. His authority, to be sure, has been
considered not to be of much weight.
The proper question, however, appears to be, whether the Greeks and
Romans used diamonds for cutting and engraving other stones or glass.
Natter, in his work already noticed, thinks they were employed on some
antique engravings. His authority is deserving respect. But if they
were employed on other stones, the authority which at present directs
us, confidently alleges they did not employ them in cutting glass; but
he points out the mode in which that article was wont to be divided, in
the following terms: “They used for that purpose emery, sharp-pointed
instruments of the hardest steel, and a red-hot iron, by which they
directed the rents at their pleasure.”
The first mention which appears to occur of the use of the diamond for
this purpose, is recorded of Francis I. of France, who, fond of the
arts, sciences, and new inventions, wrote a couple of lines with a
diamond, on a pane of glass in the Castle of Chambord, to let Anne de
Pisseleu, Duchess of Estampes, know that he was jealous.
About 1652, festoons and other ornaments, cut with a diamond, were
made on Venetian glasses; then considered the best. Schwanhard was
a professed adept in that art; and since his time an artist of the
name of John Rost, of Augsburg, cut some drinking glasses, which were
purchased by the Emperor Charles VI., at an extravagant price.
ETCHING ON GLASS.
An acid to dissolve siliceous earth was discovered as late as 1771, by
the celebrated chemist Scheele, in _sparry fluor_. It is conceived that
this cannot be of older date than that period; but it is alleged that
an acid was discovered as early as the year 1670, by Henry Schwanhard.
It being said that some aquafortis had dropped, by accident upon his
spectacles, the glass being corroded by it, he thence learned to
improve the liquid that he could etch figures and write upon glass. How
he prepared this liquid is a secret which has not been revealed. The
_Teutsche Akedemie_ says on this subject, that he, by the acuteness of
his genius, proved that which had been considered impossible could be
accomplished; and found out a corrosive so powerful that the hardest
crystal glass, which had hitherto withstood the force of the strongest
spirits, was obliged to yield to it, as well as metals and stones. By
these means he delineated and etched, on glass, figures of men, in
various situations, animals and plants, in a manner perfectly natural,
and brought them to the highest perfection.
The glass proposed to be etched is made perfectly clean and free from
grease; then the figure is covered with a varnish; then an edge of wax
being raised round the glass, the acid is poured in, and the whole
ground on the exterior of the figures appears rough, whilst the figure
is preserved in its original beauty of outline, bright and smooth. This
is the mode the inventor adopted.
Professor Beckmann says, he mentioned this ancient method of etching
upon glass, to an artist of the name of Klindworth, who possessed great
dexterity in such arts, and requested him to try it; he drew a tree
with oil varnish and colours on a plate of glass, applied the acid on
the plate in the usual manner; after it had been upon the plate for a
sufficient time, poured off, and the plate afterwards cleaned of the
varnish, a beautiful tree was left bright and smooth, with a rough
back-ground. It is conceived that many great improvements may yet be
made in this process.
It appears that no other acid than that produced by the sparry fluor
is capable of corroding every kind of glass, though Baume, in his
“Chemique Experimentale,” says, that many kinds of glass may be
corroded by the marine and vitriolic acids.
In this state of uncertainty was the public mind till the year
1725, when it was thought that a recipe, older than that previously
mentioned, might possibly be discovered. Accordingly, in that year, in
the month of January, the following is said to have been transmitted
to the publisher of the “Œkonomische Encyclopedie,” by Dr. John
George Weygand, of Goldingen, which is reported to have belonged to
Dr. Matthew Pauli, of Dresden, then deceased; with which the last
named gentleman had etched, on glass, arms, landscapes, and figures
of various kinds. We find, that in it, very strong acid of nitre was
used, which entirely disengages the acid of sparry fluor, though the
vitriolic acid has been commonly employed, and figures thus produced
will appear as if raised above the plane of the glass.
This sparry fluor is found abundantly in Derbyshire, as well as in the
mines of Germany. Theophrastus is the first who notices the effect of
sparry fluor, by observing that there are certain stones which, when
added to silver, copper, and iron ores, become fluid. It appears that
Cronstedt was the first systematic writer who gave it a name.
When _spiritus nitri per distillationem_ has passed into the recipient,
ply it with a strong fire, and when well dephlegmated, pour it, (as
it corrodes ordinary glass,) into a Waldenburg flask; then throw into
it a pulverised green Bohemian emerald, otherwise called _hesphorus_,
(which, when reduced to powder and heated, emits in the dark a green
light,) and place it in warm sand for twenty-four hours. Take a piece
of glass, well cleaned, and freed from all grease by means of a ley;
put a border of wax round it, about an inch in height, and cover it
equally all over with the above acid. The longer you let it stand,
so much the better; and at the end of some time the glass will be
corroded, and the figures which have been traced out with sulphur and
oil varnish will appear as if raised above the plane of the glass.
HYDROMETERS.
The Hydrometer is an instrument for admeasuring liquids; by it the
strength or specific gravity of different fluids is discovered, by
the depth to which it sinks in them. It has been chiefly used for
discovering the contents of different salt waters, without analysis,
and is now almost entirely used by persons connected with the
spirit-trade, to ascertain the different degrees of strength, and what
alloy they will bear; hence its utility to the manufacturer and the
excise-officer is apparent.
The laws respecting the comparative weight of different fluids, as well
as of solid bodies immersed in them, was first discovered by that great
geometrician Archimedes. It may be far from improbable that Archimedes
constructed that instrument himself; and if it should appear that he
did, it must have happened two hundred and twelve years before the
Christian era.
The most ancient mention of this instrument by its specific name,
occurs in the fifth century of our era, upon the following occasion.
The anecdote is very singular and affecting, and also evinces the
incapacity of humanity to act consistent and as it ought, when we
suffer ourselves to be directed by passions unworthy of the human
character.
It is first discovered in those letters of Synesius to the philosophic
and beautiful Hypatia. We trust we may be excused the liberty we
propose to take in detailing this circumstance, which is comparatively
little known; and as its interest also recommends it, this furnishes an
additional motive.
Hypatia was the daughter of Theon, an eminent mathematician of
Alexandria, some of whose writings are still extant. By her father
she was instructed in the mathematics, and from other great men,
who at that period abounded in Alexandria, she learned the Platonic
and Aristotelian philosophy, and acquired such a knowledge of these
sciences, that she taught them publicly, with the greatest applause.
She was young and beautiful, had a personable figure, was sprightly
and agreeable in conversation, though, at the same time, modest; and
she possessed the most rigid virtue, which was proof against every
temptation. She conducted herself with so much propriety towards
her lovers, that they never could obtain more than the pleasure of
her company, and hearing her discourse; and with this, which they
considered as an honour, they were contented. Those who were so daring
as to desire further communion she dismissed; and even destroyed
the appetite of one of her admirers, who would not suffer her to
philosophise, by means of some strong preparation, which others appear
not to have since imitated.
She suffered so cruel a death, that had she been a Christian, and
suffered from Pagan error, her name would have been ranked among its
most honoured victims in the list of martyrology; but being a Pagan,
and suffering from the persecution of superstitious and anti-Christian
zeal, she is honoured among the foremost of martyrs to celestial
philosophy.
The name of the Christian patriarch, at that period in Alexandria, was
Cyrill, whose family had, for upwards of a hundred years before his
time, produced bishops, who had been much more serviceable to their own
family connections than they had ever been towards the propagation of
the Christian faith. The present was proud, litigious, and revengeful,
vindictive and intolerant to the last degree; his ignorance debasing
his own character as a man, and scandalising the religion of which he
was so unworthy a minister. He stupidly conceived himself sanctioned
in everything which his foolish and mistaken ideas might dictate to be
for the glory of God, and acted as a persecutor, prosecutor, judge, and
executioner: he had condemned Nestorias without hearing his defence.
As the city of Alexandria was then very flourishing on account of its
extended commerce, the emperor had there allowed greater toleration and
more peculiar privileges to all religions, than in any other place:
it consequently contained, among others, a great number of Jews, who
carried on a most extensive trade, as well as a great many Pagan
families. In the eyes of the bigot Cyrill this was wrong; he would have
the sheep-fold clean, and the Jews must be banished. The governor,
however, who was a man of prudence and sober discretion, much better
acquainted with the real interests of the city, opposed a measure he
saw replete with mischief, and even caused to be condemned to death a
Christian profligate, who had injured the Jews. This malefactor was, by
the express order of Cyrill, buried in the church as a martyr; and he
collected an army of five hundred lazy monks, who abused the governor
in the public streets, and excited an insurrection among the people
against the Jews, so that the debased race of Abraham was expelled from
the city where they had so long existed unmolested from the time of
Alexander the Great.
Cyrill, one day, whilst looking for objects of persecution, saw a
number of carriages, attended with servants, belonging to the first
families in the city, before a certain house. Inquiring what was the
cause of the assembly, he was informed that it was the habitation of
the lovely Hypatia, who, on account of her extensive learning and very
eminent talents, was visited by people of the first respectability.
This afforded to the malignant priest a sufficient object for the
exercise of his jealousy against the meritorious, the unoffending, the
beautiful Hypatia. He from that moment resolved upon her destruction.
Accordingly he lost no time in exciting his myrmidons, the monks and
priests, those who should have been the ministers of that religion
which they professed to teach, to destroy the fair philosopher.
They accordingly, with diabolical rage, and instigated by infernal
cruelty, took the earliest opportunity to seize her, hurried her to the
church--the temple of peace and good-will--which they violated by an
offence at which humanity must shudder; having torn the clothes from
her delicate form, they tore the flesh from her bones with potsherds,
then dragged her mangled body about the city, and afterwards burnt it.
This demoniacal tragedy took place in the year 415, and was perpetrated
by the professed servants of Him who came into world to save those
which were lost--to preach peace and good-will to all men. The
impressions which such an event made upon people of every persuasion
may be conceived; they admit not of description from a feeble pen: but
we may ask the question, was it such a transaction as was calculated to
make converts to the doctrines of Christianity?--whose avowed motive
and maxim is, in the words of Milton,
“By winning words, to conquer willing hearts,
And make persuasion do the work of fear.”
All historians are not agreed in some circumstances of the preceding
relation; but they generally unite in bestowing praise upon Hypatia,
whose memory was long honoured by her grateful and affectionate
scholars, among whom was Synesius, of a noble Pagan family, who had
cultivated philosophy and the mathematics with the utmost ardour,
and who had been one of her most intimate friends and followers. On
account of his learning and virtues, many eminent talents, and open
disposition, the inhabitants of Ptolemais were desirous he should be
bishop, having been previously employed on many public and important
concerns with success. After modestly desiring, for a long period,
that they would fix their choice upon a more worthy object, they still
persisting, he assented, upon condition that he was not to believe
in the resurrection, to which he could not at that time bring his
internal conviction: he suffered himself to be baptised, and became
their bishop; he was confirmed by the orthodox patriarch Theophilus,
the predecessor of Cyrill, to whose jurisdiction Ptolemais belonged:
he afterwards renounced his error respecting the resurrection. This
learned man evinced his gratitude to Hypatia, by the honourable mention
which he made of her in some of his writings, still preserved.
In his fifteenth letter to her, he tells Hypatia, that he was so
unfortunate, or found himself so ill, that he wished to use an
hydroscopium (the Greek for hydrometer), and he requests that
she would cause one to be constructed for him. He says, “It is a
cylindrical tube, of the size of a reed or pipe; a line is drawn upon
it lengthways, which is intersected by others, and these point out the
weight of water. At the end of the tube is a cone, the base of which
is joined to that of the tube, so that they have both only one base.
This part of the instrument is called _baryllion_. If it be placed in
water, it remains in a perpendicular direction, so that one can readily
discover by it the weight of the fluid.”
Petau, who published the works of Synesius, in the year 1640,
acknowledges that he did not understand this passage. An old scoliast,
he says, who had added some illegible words, thought it was a
water-clock; but the ellepsydra was not immersed in water, but filled
with it. He therefore thought that it might allude to the chorobates,
which Vitruvius describes as an instrument employed in levelling; but
it appears that Synesius, who complained of ill health, could have no
occasion for such an instrument. Besides, no part of that instrument he
describes, has any resemblance to the one described by Synesius.
From the works of Fermat, an excellent mathematician, and a very
learned man, well acquainted with antiquities and the works of the
ancients, we give the following explanation concerning the hydroscopium
of Archimedes, as this article would be incomplete without it:--
“It is impossible,” says he, “that the _hydroscopium_ could be the
level or _chorobates_ of Vitruvius, for the lines on the latter were
perpendicular to the horizon, whereas the lines on the former were
parallel to it. The hydroscopium was undoubtedly a hydrometer of the
simplest construction. The tube may be made of copper, and open at the
top; but at the other end, which, when used, is the lowest, it must
terminate with a cone, the base of which is added to that of the tube.
Lengthwise, along the tube, are drawn two lines, which are intersected
by others, and the more numerous these divisions are, the instrument
will be so much the more correct.--When placed in water it sinks to a
certain depth, which will be marked by the cross-lines, and which will
be greater, according to the lightness of the water.” A figure which is
added, might have been dispensed with. When a common friend of Fermat
and Petau showed it to the latter, he considered it to be so just,
and explanatory of the real meaning of Synesius, that he wished to be
allowed the opportunity of introducing it in a new edition of the works
of Synesius.
_FINIS._
J. S. Pratt, Stokesley, Yorkshire.
Transcriber’s Notes
Punctuation, hyphenation, and spelling were made consistent when a
predominant preference was found in this book; otherwise they were not
changed.
Many typographical errors were corrected; occasional unbalanced
quotation marks retained.
Text uses both “Guttenberg” and “Guttenburg”, “Helvelius” and
“Hevelius”; both versions retained.
Page 18: “documentary” was printed as “documentry”; changed here.
Page 33: “transcendant” was printed that way.
Page 33: The opening quotation mark preceding “A complete Course of
Lithography” was added by Transcriber. Other punctuation and spelling
within that title has not been changed, but some of it differs from
what was printed in the English translation of the cited book.
Page 54: The period after “Deity” in “offensive to the Deity. that the
great majority” probably should be a semi-colon.
Pages 63 and 249: A question mark is followed by a lower-case word.
Page 109: “Chardiu” was printed that way.
Page 139: “It last it changed colours” should begin with “At”.
Page 171: “the bull of Æolus” probably is a misprint for “ball”.