VOL.5, No. 5
AN INEXPENSLYE DESICCATOR
597
AN INEXPENSIVE DESICCATOR JESSE E. DAYAND EARL W. W A L TAB ~ , OHIOSTATE UNIVERSITY, COLU~U OHIO S, The quantity of so-called "returnable" equipment put in a student lahoratory locker is generally governed by several or all of the following Factors: (a) the needs of the course; (b) the capacity of the locker; ( 6 ) the financial outlay involved; (d) the extent of usage; (e) convenience to the student and the supply room; (f) sound educational practice; and (g) laboratory administration. In the larger laboratories where the students have but slight, if any, personal acquaintance, there is a quite human tendency to accept a correspondingly smaller measure of responsibility for apparatus intended for general use. Not infrequently, this condition results in a nearly total withdrawal of general apparatus from the laboratory and sometimes the more common reagents as well. I t is very seldom that a desiccator is included in a locker outfit for firstyear students. In our more advanced course in general chemistry this item of equipment is needed in several of the exercises. The cost of the smallest one on the market has made its inclusion prohibitive. Recently we converted an American-made Stender preparation dish (diameter = 5.8 cm.;height = 9.6 cm.) into a very satisfactory desiccating vessel. The cost of the dish is about one-fifth of that of thc standard four-inch desiccator and has a capacity of one No. 00 porcelain crncible and lid. It is equipped with a heavy accurately ground cover and when the ground surfaces are lightly coated with a mixture of vaseline and beeswax gives an air-tight joint. A 5 cm. square of 10 mesh common wire gauze (C) with the corners turned down to serve as legs and the center slightly depressed provides a good false bottom on which the crucible is placed. Sufficient of the solid desiccating agent (generally calcium chloride) is used so that it does not quite come in contact with the platform of the gauze when the legs of the latter are resting on the bottom of the vessel. An ordinary 10 or 13 cm. forcep is used in the' handling of the crucible and lid.
