The first step in chemistry : a new method for teaching the elements of the science / by Robert Galloway.

  • Galloway, Robert, 1822-1896
Date:
1860
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Licence: Public Domain Mark

Credit: The first step in chemistry : a new method for teaching the elements of the science / by Robert Galloway. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    ELEMENTS AJ5 D COMPOUNDS. three states; the three states are, the solid, the liquid, and the gaseous or aeriform. Every one is aware that solid and liquid bodies possess weight, but the fact that gaseous bodies possess weight is not so generally known; the following experiments are therefore given to teach the learner this fact, and also that all gases have not the same weight, but that some are heavier, some are lighter, than others; in other words, gases differ in weight like solids and liquids. EXPERIMENTAL EXERCISES ON THE WEIGHT OF GASES. 1. Fill a small balloon of goldbeater’s skin with hydro- gen gas (as directed in Expt. 52, p. 27), the balloon, after it is filled with the gas, will rise, if allowed, to the ceiling of the class-room, because hydrogen gas is much lighter (fourteen and a half times) than atmospheric air; in fact, hydrogen is the lightest body in nature. 2. Prepare some carbonic acid gas as directed in Expt. 78 ; let the exit tube of the apparatus in the present experiment dip into a dry glass vessel (the tube ought to reach to the bottom of the vessel); the precipitating vessels (Fig. 32), described in the chapter on the con- struction of apparatus, &c., are very suitable for the experiment. As soon as the vessel is filled with the gas, which is ascertained by a candle being extinguished when introduced just below the edge of the vessel, pour the gas as you would a liquid into another vessel of similar size and shape. Prove that the gas has been really transferred from the one vessel to the other by introducing a lighted candle (Fig. 8) first into the vessel originally containing it (in which the candle ought now to burn), and then into the one which ought now, if the experiment has been properly performed, to contain it, and in which the candle ought not now to burn. If great care be observed in the experiment, it may be transferred from one vessel to the other three or four times. This experiment shows the great density of the gas ; it also shows the incapability of the gas to support the combus- tion of a candle. 3. Fill a wide and deep glass jar* half full of carbonic * The jar ought to be about twelve or fourteen inches wide, and about two feet in depth.
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