The recomposition of this acid I shall show you, by burning some of its basis, which you see here, in a retort full of oxygen gas. The heat of a candle is all that is required for this combustion.—
EMILY.
The light is astonishingly brilliant, and what beautiful sparks it throws out!
MRS. B.
The result of this combustion is the boracic acid, the nature of which, you see, is proved both by analytic and synthetic means. Its basis has not, it is true, a metallic appearance; but it makes very hard alloys with other metals.
EMILY.
But pray, Mrs. B., for what purpose is the boracic acid used in manufactures?
MRS. B.
Its principal use is in conjunction with soda, that is, in the state of borat of soda, which in the arts is commonly called borax. This salt has a peculiar power of dissolving metallic oxyds, and of promoting the fusion of substances capable of being melted; it is accordingly employed in various metallic arts; it is used, for example, to remove the oxyd from the surface of metals, and is often employed in the assaying of metallic ores.
Let us now proceed to the FLUORIC ACID. This acid is obtained from a substance which is found frequently in mines, and particularly in those of Derbyshire, called fluor, a name which it acquired from the circumstance of its being used to render the ores of metals more fluid when heated.