To Give a Piece of Charcoal a Rich Coat of Silver.
Lay a crystal of nitrate of silver upon a piece of burning charcoal; the metallic salt will catch fire, and throw out the most beautiful scintillations that can be imagined. The silver is reduced, and, in the end, produces upon the charcoal a very brilliant appearance.
Many animal and vegetable substances, consist, for the most part, of carbon, or charcoal, united with oxygen and hydrogen, which remember, together combined, form water. Now oil of vitriol or strong sulphuric acid, has so powerful an affinity or so great a thirst for water, that it will abstract it from almost any body in which it exists. If you pour some of this acid on a lump of sugar, or place a chip of wood in a small quantity of it, the sugar or wood will become speedily blackened, that is charred, in consequence of the oxygen and hydrogen being removed by the sulphuric acid, and only the carbon or charcoal left.
When Cleopatra dissolved pearls of wondrous value in vinegar, she was unwittingly giving an example of chemical affinity. The pearl is simply carbonate of lime stored up by the oyster in layers. Consequently the precious jewels were decomposed by the greater affinity or fondness of lime for the acetic acid in the vinegar, than for the carbonic acid with which it had been before united. This was an example of inconstancy in strong contrast with the conduct of their owner, who chose death rather than become the wife of her lover’s conqueror.