No. XXXV.
ANCIENT CHEMISTRY, &c.
_Distillation._--It has been questioned whether the ancients were
acquainted with this art, but a passage of Dioscorides not only
indicates the practice, but shows that the name of its principal
instrument, the alembic, was derived from the Greek language. Pliny
gives the same explanation, as Dioscorides does, of the manner of
extracting quicksilver from cinnabar by distillation. And Seneca
describes an instrument exactly resembling the alembic. Hippocrates even
describes the process of distillation. He talks of vapours from the
boiling fluid, which meeting with resistance stop and condense, till
they fall in drops. Zosimus of Panopolis, an Egyptian city, desires his
students to furnish themselves with alembics, gives them directions how
to use them, describes them, and presents drawings of such as best
deserve to be employed in practice.
_Alcalis and Acids._--Of the substances promiscuously termed lixivial
salt, sal alcali, rock-salt, &c., Aristotle speaks, when he says that
in Umbria the burnt ashes of rushes and reeds, boiled in water, yield a
great quantity of salt. Theophrastus observes the same. Varro relates of
dwellers on the borders of the Rhine, who having neither sea nor pit
salt, supply themselves by means of the saline cinders of burnt plants.
Pliny speaks of ashes as impregnated with salts, and in particular of
the nitrous ashes of burnt oak; adding, that these salts are used in
medicine, and that a dose of lixivial ashes is an excellent remedy.
Hippocrates, Celsus, Dioscorides, and especially Galen, often recommend
the medical use of sal alcali. To the mixture of acids and alcali, Plato
ascribed fermentation. Solomon seems to have known this effect of them,
when he speaks of “vinegar upon nitre.”
_Cleopatra’s Pearl._--A convincing proof of the ability of the ancients
in chemistry is the experiment with which Cleopatra entertained Marc
Antony, in dissolving before him, in a kind of vinegar, a pearl of very
great value, (above 45,450_l._ sterling.) At present we know not of any
“vinegar” that can produce this effect; but the fact is well attested.
Probably the queen added something to the vinegar, omitted by the
historian. The aid of Dioscorides, surnamed Phacas, who was her
physician, might have enabled her thus to gain her wager with Marc
Antony, that she would exceed him in the splendour and costliness of her
entertainment. But Cleopatra herself was a chemical adept, as appears
from some of her performances still in the libraries of Paris, Venice,
and the Vatican. And Pliny informs us of the emperor Caius, that by
means of fire he extracted some gold from orpiment.
_Malleability of Glass._--The method of rendering glass ductile, which
is to us a secret, was assuredly a process well known to the ancients.
Some still doubt of it, as others have of the burning glasses of
Archimedes. Because forsooth they do not know how it could be effected,
they will not admit the fact, notwithstanding the exact accounts we have
of it, till somebody again recovers this lost or neglected secret, as
Kircher and Buffon did that of Archimedes’s mirrors. Pliny says, the
flexibility of glass was discovered in the time of Tiberius; but that
the emperor fearing lest gold and silver, those most precious metals,
should thereby fall in their value, so as to become contemptible,
ordered the residence, workhouse, and tools of the ingenious artisan to
be destroyed, and thus strangled the art in its infancy. Petronius is
more diffuse. He says, that in the time of Tiberius there was an
artificer who made vessels of glass, which were in their composition and
fabric as strong and durable as silver or gold; and that being
introduced into the presence of the emperor, he presented him with a
vase of this kind, such as he thought worthy of his acceptance. Meeting
with the praise his invention deserved, and finding his present so
favourably received, he threw the vase with such violence upon the
floor, that had it been of brass it must have been injured by the blow;
he took it up again whole, but dimpled a little, and immediately
repaired it with a hammer. While in expectation of ample recompense for
his ingenuity, the emperor asked him whether any body else was
acquainted with this method of preparing glass, and being assured that
no other was, the tyrant ordered his head to be immediately struck off;
lest gold and silver, added he, should become as base as dirt. Dion
Cassius, on this head, confirms the attestations of Pliny and Petronius.
Ibn Abd Alhokim speaks of malleable glass as a thing known in the
flourishing times of Egypt. Greaves, in his work on Pyramids, mentions
him as a celebrated chronologist among the Arabians, and cites from him
that “Saurid built in the western pyramid thirty treasuries, filled with
store of riches and utensils, and with signatures made of precious
stones, and with instruments of iron and vessels of earth, and with arms
which rust not, and with glass which might be bended, and yet not
broken, &c.” There is, however, a modern chemical composition, formed of
silver dissolved in acid spirits, and which is called _cornu lunæ_, or
horned moon, a transparent body, easily put into fusion, and very like
horn or glass, and which will bear the hammer. Borrichius, a Danish
physician of the seventeenth century, describes an experiment of his
own, by which he obtained a pliant and malleable salt: he gives the
receipt, and concludes from thence, that as glass for the most part is
only a mixture of salt and sand, and as the salt may be rendered
ductile, glass may be made malleable: he even imagines that the Roman
artificer, spoken of by Pliny and Petronius, may have successfully used
antimony as the principal ingredient in the composition of his vase.
Descartes supposed it possible to impart malleability to glass, and
Morhoff assures us that Boyle was of the same opinion.
_Painting on Glass._--This art, so far as it depends upon chemistry, was
carried formerly to high perfection. Of this we have striking instances
in the windows of ancient churches, where paintings present themselves
in the most vivid colours, without detracting from the transparency of
the glass. Boerhave and others observe, that we have lost the secret to
such a degree, that there are scarcely any hopes of recovering it. Late
experiments go far towards a successful restoration of this art.
_Democritus._--This eminent man, who was a native of Abdera in Thrace,
flourished upwards of four centuries before the Christian æra. For the
sake of acquiring wisdom he travelled into Egypt, and abode with the
priests of the country. He may be deemed the father of experimental
philosophy. It is affirmed that he extracted the juice of every simple,
and that there was not a quality belonging to the mineral or vegetable
kingdoms that escaped his notice. Seneca says, that he was the inventor
of reverberating furnaces, the first who gave a softness to ivory, and
imitated nature in her production of precious stones, particularly the
emerald.
_Gunpowder._--Virgil and his commentator Servius, Hyginus, Eustathius,
La Cerda, Valerius Flaccus, and many other authors, speak in such a
manner of Salmoneus’s attempts to imitate thunder, as suggest to us that
he used a composition of the nature of gunpowder. He was so expert in
mechanics, that he formed machines which imitated the noise of thunder,
and the writers of fable, whose surprise in this respect may be compared
to that of the Mexicans when they first beheld the fire-arms of the
Spaniards, give out that Jupiter, incensed at the audacity of this
prince, slew him with lightning. It is much more natural to suppose that
this unfortunate prince, as the inventor of gunpowder, gave rise to
these fables, by having accidentally fallen a victim to his own
experiments. Dion and Joannes Antiochenus report of the emperor
Caligula, that he imitated thunder and lightning by means of machines,
which at the same time emitted stones. Themistius relates, that the
Brachmans encountered one another with thunder and lightning, which they
had the art of launching from on high at a considerable distance.
Agathias reports of Anthemius Traliensis, that having fallen out with
his neighbour, Zeno the rhetorician, he set fire to his house with
thunder and lightning. Philostrates, speaking of the Indian sages, says,
that when they were attacked by their enemies they did not leave their
walls to fight them, but repelled and put them to flight by thunder and
lightning. In another place he alleges that Hercules and Bacchus
attempting to assail them in a fort where they were entrenched, were so
roughly received by reiterated strokes of thunder and lightning,
launched upon them from on high by the besieged, that they were obliged
to retire. The effects ascribed to these engines could scarcely be
brought about but by gunpowder. In Julius Africanus there is a receipt
for an ingenious composition to be thrown upon an enemy, very nearly
resembling that of gunpowder. But that the ancients were acquainted with
it seems proved beyond doubt, by a clear and positive passage of an
author called Marcus Græcus, whose work in manuscript is in the Royal
Library at Paris, entitled “Liber Ignium.” The author, describing
several ways of encountering an enemy, by launching fire upon him, among
others gives the following receipt:--Mix together one pound of live
sulphur, two of charcoal of willow, and six of saltpetre; reduce them to
a very fine powder in a marble mortar. He directs a certain quantity of
this to be put into a long, narrow, and well-compacted cover, and so
discharged into the air. Here we have the description of a rocket. The
cover with which thunder is imitated he represents as short, thick, but
half-filled, and strongly bound with packthread, which is exactly the
form of a cracker. He then treats of different methods of preparing the
match, and how one squib may set fire to another in the air, by having
it enclosed within it. In short, he speaks as clearly of the composition
and effects of gunpowder as any body in our times could do. This author
is spoken of by Mesue, an Arabian physician, who flourished in the
beginning of the ninth century. There is reason to believe that he is
the same of whom Galen speaks.