Page:The fairy tales of science.djvu/66

 them in the water of the boundless ocean, the placid lake, and the murmuring rivulet; in the floating cloud and the jagged iceberg; in the raindrop, the hailstone, and the snow-flake; in the jewel that glitters upon the bosom of the rose, and in the tear that falls from the mourner's eye!

Potassium is not the only substance that decomposes water. Everybody is familiar with the fact that iron rusts when placed in water. Now the rusting of iron is a similar phenomenon to the conversion of potassium into potash; they both depend upon the absorption of oxygen. At a red heat, iron decomposes water very rapidly. When steam is made to pass through a long red-hot iron tube it is resolved into its elements. The oxygen unites with the iron to form rust, and the hydrogen is set free. By weighing the tube before and after the operation, the chemist is able to determine the proportion in which the two elements are combined.

In a hundred parts by weight of water he invariably finds eighty-nine of oxygen and eleven of hydrogen.

We may employ our old friend the Amber Spirit to separate the elements of Water, as this versatile being is a most skilful analytical chemist. The Spirit can set free the oxygen and hydrogen in two distinct streams of bubbles; whereas, the human operator can only liberate one of these gases by forcing the other to combine with some new body.

We have spoken of the inflammable nature of