crystalline mass of coke, are mere modifications of one substance.
Again, this piece of graphite is chemically the same substance, as it is simply an aggregate of carbon atoms; but it has none of the properties of charcoal. It has a metallic leaden-grey lustre, whence its familiar name of black-lead. It burns with great difficulty; it is greasy to the touch, and it leaves dark traces when rubbed upon paper.
But the most remarkable form assumed by carbon is that of the diamond. This precious gem occurs in nature in regular crystals, usually colourless, but sometimes yellow and brown. Now, we are convinced that this brilliant and transparent body is made up of the very same atoms as those which go to form the dull black mass of charcoal! The alchemist has not yet succeeded in making diamonds, but he has already transmuted diamonds into coke. Who knows but what he may reverse this transmutation before long!
When we find a single element assuming these Protean shapes, we must admit that the notions of the old alchemists were far from being extravagant. To a person ignorant of chemistry it would appear much more probable that the metals are modifications of one substance, than that the diamond is merely crystallized charcoal.
Sulphur may be obtained in various forms. The roll-sulphur or brimstone, and the fine powder called flowers of sulphur, are probably the only forms
