The Romance of Modern Chemistry

HOW MAN COMPETES WITH NATURE the latter element, forming prussic acid, or hydrocyanic acid, as the chemist calls it; and when prussic acid is neutralised with potash we obtain the salt potassium cyanide, a very poisonous compound of potassium, carbon, and nitrogen. Potassium cyanide can be very easily melted in an iron dish, and in the molten state readily absorbs oxygen from the air, forming a salt called potas- sium cyanate, a compound of potassium, carbon, nitrogen, and oxygen. If this substance is dissolved in water and sulphate of ammonia added, we get a double exchange taking place, whereby ammonium cyanate and potassium sulphate are formed. This gradual building up of carbamide may be repre- sented graphically in the following manner:— Ammonium sulphate Carbon Hydrogen Nitrogen Potash Carbamide It may be objected that besides the four elements, carbon, hydrogen, oxygen, and nitrogen, three compounds have been introduced into this synthesis, namely, potash, water, and ammonium sulphate. If space and the reader’s patience permitted, it might, however, be shown that these compounds also can be built up out of their con- stituent elements, so that the whole chain is complete, 252