Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER IH HYDROGEN Preparation of Hydrogen. — In the preceding chapters reference has been made to the fact that water is composed of hydrogen and oxygen. We may now study hydrogen, oxygen, and water separately and in detail. Hydrogen, although it had been obtained and partly examined by several earlier investigators, was first accurately studied by Cavendish in 1766. In 1781 he made the additional discovery that water is the only product of its combustion; and, on account of this fact, Lavoisier gave it its present name, which signifies "water producer." It may be easily obtained from water as follows: — Experiment 4. — Wrap a piece of sodium in a small piece of filter paper, grasp it with a pair of crucible tongs, dip it into kerosene, and bring it under the mouth of an inverted test tube containing water. The water is brought into the test tube by simply filling the tube in an upright position, placing the thumb over the open end of the tube and then inverting the test tube in a pan of water. The tube should be completely filled with water. The metallic sodium will at once act upon the water, and bubbles of gas will be set free and will rise in the tube. When the tube is nearly full of gas, its mouth is again closed with the thumb, and it is removed from the pan of waterand turned mouth upward. Upon removing the thumb and instantly lighting the gas with a match or with the flame of the Bunsen burner, the gas in the tube will be seen to burn with a pale bluish flame. This gas is hydrogen. F1G. 2.—Preparation of Hydrogen with Sodium. If a piece of sodium is brought directly into contact with water, the action is very violent. It is for the purpose of diminishing this violence that the sodium is wrapped in filter paper and dipped in kerosene, for these two su...