Page:The fairy tales of science.djvu/112

86 known to the reader. The alchemist, however, procures sulphur in beautiful semi-transparent crystals; in needle-like prisms of a brownish-yellow colour; and in a soft and sticky mass, which may be drawn out into elastic threads, and which greatly resembles shoemaker's wax.

Phosphorus is equally changeable, and may be obtained in no less than five different forms. Let us compare ordinary phosphorus with its most striking modification, which has been designated amorphous phosphorus. Ordinary phosphorus is a colourless waxy-looking solid; the amorphous phosphorus is opaque, and of a brownish-red colour. The former is easily fusible, very inflammable, and luminous in the dark; the latter may be heated in the open air without change, until the temperature reaches 500°, when it is converted into ordinary phosphorus. Great caution is required in handling the ordinary phosphorus, as the heat of the hand is sometimes sufficient to inflame it; but the philosopher who discovered the amorphous phosphorus is in the habit of carrying this variety loose in his pocket. Common phosphorus dissolves in bisulphide of carbon; the altered phosphorus is insoluble in that liquid. The former is very poisonous; the latter, in the same dose, has no effect on the animal system.

These marvellous differences are inexplicable. We are able to change the ordinary phosphorus