place blocks of wood under the bottom of the bottle to prevent superheating. A stirring device on the bath is very desirable. Some water will expand from the sample bottle into the bulb, B. Any desired amount of vacuum may be produced by lowering the leveling bulb containing mercury attached to the bottom of the pipet at L. If any water accidentally enters the gas pipet, G, the mercury may be lowered until the water is drawn into the reservoir, W. Stopcock, S2, is then turned so that the by-pass, T, is open and the gas forced through, O, into a storage pipet or buret. Then the mercury is lowered until it reaches stopcock, S2, again, which is then turned so that as the mercury is raised again the water from W floats on top. It is carefully raised until the bend, K, is reached where the water flows back into the condenser tube. Before attempting this operation the collected gas already extracted must be removed as described.After all gases have been removed from the sample, the water in bulb, B, is boiled for a couple of minutes to remove any gases present and then the stopper, Z, is loosened. By lowering the leveling bulb, the gas in the condenser tube and bulb is drawn over into the pipet, water entering the system through hole H. The bend, K, and the joint between the condenser tube and the capillary tube, E, enables one to make a clean separation of the gas and water. It was found that if a simple bend was used some gas always remained at the top of the bend. Summary A modification of the usual apparatus for removing dissolved gases in water has been described.
