CORRESPONDENCE HYDROGEN SULFIDE GENERATOR To the Editor DEARSIR: Enclosed is a drawing of a home-made hydrogen sulfide generator, which has given satisfaction in this laboratory for many years. In the drawing, a steel drum,preferably zinc coated, is represented by a. Axially mounted thereon by nuts and fiber washers is the pipe b, provided with the outlet,
'' At the bottom
Of this drum are Outlets such as through which water may enter or leave the drum. This drum is contained in the larger drum, i, which carries a t its base the pipe j. This serves as a guide for the floating inner drum as well as a conduit for the gas,
g. After installation about a gallon of coal oil, f, is poured in a t the opening, h, which such drums always carry. This prevents the gas from dissolving in the water. The pipe is continued to the fitting, 1, which provides an outlet for any water that may accidentally get into the line. Further continuation provides connections with the generator, n, and the wash bottle, t. The generator may be the ordinary five-gallon water bottle in which is placed a plentiful supply of iron sulfide. The cork may carry a three-holed stopper. One opening is for the exit, o, another for the funnel, p, which should be extended to the bottom of the bottle by rubber hose attached to the funnel and the other may cany a syphon for emptying the spent acid. The service tubes, u and er, should be of thick-walled onenun. capillary tubing, connected by a considerable length of rubber tubing. This mounting will slow up the exit of the gas and provide flexibility for shaking the container of the solution to be precipitated. No stopcock is necessary if the acidulated water, w,is of sufficient depth to resist the head of water in the drums. The spent acid in the generator may be removed, without opening the system by the following procedure. Water is run into the generator to force all the gas back into the drum, the exit, o, closed and the spent acid and water drained off. The generator is then filled with fresh water, o opened and extra water again drained as the gas flows back from the drum to the generator. This set-UDhas been found su~eriorto the usual automatic generator, because the acid remains in contact with the iron sulfide until exhausted and little servicing is needed. OCCIDSNTAL COLLEOE ~ o ANceLEs, s Cn~~aonma
E.E. CHANDLER
