A CONVENIENT LECTURE APPARATUS FOR GASES EVERETT THOMAS HOPPE St. Michael Central High School, Chicago, Illinois
RECENTLY, because of the need of a safe carbon monoxide collector, I constructed the following type of 5
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apparatus which, in the opinion of several others, is more suitable than the pneumatic trough for certain experiments. A long glass cylinder of large diameter is secured. To the top and bottom, respectively, a one-hole stopper and a two-hole stopper are fitted. Into the bottom stopper a small bent glass tube ( A ) and a long tube (B) are introduced. B is as high as the cylinder so that, when the apparatus is filled with water, no water can be forced into the generating chamber. Into the top, a bent tube (C) is introduced. A serves as a water inlet and outlet, B as the gas inlet, and C as the gas outlet. To prepare the apparatus for use, water is run in through A until the apparatus is completely filled. (To collect gases soluble in water, other liquids might be used, although this is not as convenient.) Then the stopcocks, 1, 2, and 3, are closed. To collect the gas, stopcocks 1 and 2 are opened, thereby permitting the water to run out and the gas to enter. The gas literally rushes into the vacuum formed by the falling water. Its passage through the water partially purifies the gas. To obtain the gas for burning or other purposes, it is merely necessary to open stopcocks 1 and 3 and run water into the system. To mix the gas with air or some other gas, the apparatus is only partially filled. Then tube Cis connected to the gas source or left open to the air, stopcocks 1 and 3 opened, and the water permitted to run out. If the cylinder is graduated, known volumes of gases can be forced out or mixed. Another feature of the apparatus is its safety in combustion experiments. If an explosion does occur, the rubber stoppers are simply forced out and the cylinder remains intact.
