Cuvier, in one of a series of lectures, delivered at Paris, in the spring of last year, says, "the name chemistry, itself, comes from the word chim, which was the ancient name of Egypt;" and he states that minerals were known to the Egyptians "not only by their external characters, but also by what we at the present day call their chemical characters." He also adds, that what was afterwards called the Egyptian science, the Hermetic art, the art of transmuting metals, was a mere reverie of the middle ages, utterly unknown to antiquity. "The pretended books of Hermes are evidently supposititious, and were written by the Greeks of the lower Empire."
Crystallization.
Why are the crystals collected in camphor bottles in druggists' windows always most copious upon the surface exposed to the light?
Because the presence of light considerably influences the process of crystallization. Again, if we place a solution of nitre in a room which has the light admitted only through a small hole in the window-shutter, crystals will form most abundantly upon the side of the basin exposed to the aperture through which the light enters, and often the whole mass of crystals will turn towards it.—Brande.
Why is sugar-candy crystallized on strings, and verdigris on sticks?
Because crystallization is accelerated by introducing into the solution a nucleus, or solid body, (like the string or stick) upon which the process begins.
The ornamental alum baskets, whose manufacture was once so favourite a pursuit of lady-chemistry, were made upon this principle; the forms of the baskets being determined by wire framework, to which the crystals readily adhere.
Why is sugar-candy sometimes in large and regular crystals?
Because the concentrated syrup has been kept for several days and nights undisturbed, in a very high temperature; for, if perfect rest and a temperature of from 120° to 190° be not afforded, regular crystals of candy will not be obtained.
The manufacture of barley-sugar is a familiar example of crystallization. The syrup is evaporated over a slow heat, till it has acquired the proper consistence, when it is poured on metal to cool, and when nearly so, cut into lengths with shears, then twisted, and again left to harden.