Note.—All unknown to the ancient chemists.—A.
Sect. XLI.—Observations upon Formic Acid, and its Combinations.
This acid was first obtained by distillation from ants, in the last century, by Samuel Fisher. The subject was treated of by Margraff in 1749, and by Messrs Ardwisson and Ochrn of Leipsic in 1777. The formic acid is drawn from a large species of red ants, formica rufa, Lin. which form large ant hills in woody places. It is procured, either by distilling the ants with a gentle heat in a glass retort or an alembic; or, after having washed the ants in cold water, and dried them upon a cloth, by pouring on boiling water, which dissolves the acid; or the acid may be procured by gentle expression from the insects, in which case it is stronger than in any of the former ways. To obtain it pure, we must rectify, by means of distillation, which separates it from the uncombined oily and charry matter; and it may be concentrated by freezing, in the manner recommended for treating the acetous acid.
Sect. XLII.—Observations upon Bombic Acid, and its Combinations with Acidifiable Bases[52].
The juices of the silk worm seem to assume an acid quality when that insect changes from a larva to a chrysalis. At the moment of its escape from the latter to the butterfly form, it emits a reddish liquor which reddens blue paper, and which was first attentively observed by Mr Chaussier of the Dijon academy, who obtains the acid by infusing silk worm chrysalids in alkohol, which dissolves their acid without being charged with any of the gummy parts of the insect; and, by evaporating the alkohol, the acid remains tollerably pure. The properties and affinities of this acid are not hitherto ascertained with any precision; and we have reason to believe that analogous acids may be procured from other insects. The radical of this acid is probably, like that of the other acids from the animal kingdom, composed of charcoal, hydrogen, and azote, with the addition, perhaps, of phosphorus.
Table of the Combinations of Sebacic Acid, with the Salifiable Bases, in the Order of Affinity.
| Bases. | Neutral Salts. | ||
| Barytes | Sebat of | barytes. | |
| Potash | potash. | ||
| Soda | soda. | ||
| Lime | lime. | ||
| Magnesia | magnesia. | ||
| Ammoniac | ammoniac. | ||
| Argill | argill. | ||
| Oxyd of | |||
| zinc | zinc. | ||
| manganese | manganese. | ||
| iron | iron. | ||
| lead | lead. | ||
| tin | tin. | ||
| cobalt | cobalt. | ||
| copper | copper. | ||
| nickel | nickel. | ||
| arsenic | arsenic. | ||
| bismuth | bismuth. | ||
| mercury | mercury. | ||
| antimony | antimony. | ||
| silver | silver. | ||
Note.—All these were unknown to the ancient chemists.—A.