An introduction to the study of chemistry / by Ira Remsen.

  • Ira Remsen
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: An introduction to the study of chemistry / by Ira Remsen. Source: Wellcome Collection.

    26/410 (page 10)
    will at onee burst into flame, and the burning of the wood will take place more actively than it does in ordinary air, as may be shown by withdrawing it and again inserting it into the tube. The gas in this tube, it will be noticed, does not take Are. Without going into further details, it is clear from the above experiment that when an electric cur- rent acts on water two invisible gases are produced. We shall have occasion hereafter to study this experiment much more carefully, and we shall find that from it we can learn a great deal more than we have just learned; but our ob- ject now is to learn that an electric current can produce a chemical change. Note for Student.—The method adopted for collecting the gases is apt to appear somewhat mysterious to the beginner, and his attention is thus drawn away from the important part of the experiment. It will on this account be well for the student to familiarize himself with the method by means of a few experiments especially undertaken for the purpose. Experiment 4.—Pill a test-tube or glass cylinder with water; close the mouth with the thumb or a ground-glass plate; invert the tube, and put the mouth under water. The water stays in the tube after the thumb or glass plate is removed. (Why ?) Now take a piece of glass or rubber tubing ; put one end under the mouth of the inverted tube, and blow gently through the other end. Bubbles will rise in the tube and the water will be displaced. In this case the gases from the lungs are collected. When they come below the mouth of the tube, being lighter than water, they rise, and as the space occupied by them cannot be occupied by the water too, the latter is displaced. (See Fig. 4.) Experiment 5.—To transfer a gas from one vessel to another by displacement of water, place both vessels invert- ed in the same bath, and then gradually bring the one con-