A CONVENIENT TYPE OF WASH BOTTLE RAY WOODRIFF University of Colorado, Boulder, Colorado ,
FOR chemical work in which a wash bottle finds constant use, it is important to have one which is as convenient as possible. The advantages of the wash bottle are shown here. (1) The volume of liquid used r a n be accurately measured. r (2) The amount of wash liquid may he accurately controlled, even down to one drop. (3) The wash liquid may he directed against the precipitate with great force when desired; however, the force of washing may be easily controlled. (4) The liquid comes in contact with nothing hut glass. Although vapors go down into the rubher bulb, any material loosened by such contact does not fall into the wash liquid. (5) Use of this wash bottle eliminates the unpleasant necessity of blowing into the bottle, thus enabling one to see better what he is doing. Also burns, or disagreeable fumes from the wash liquid are avoided. When the rubber hulb, B, is pressed, the pressure in the auxiliary tuhe, A, is increased, causing valve Vz to open, thus forcing the liquid from A out through the tube C with a force proportional to the pressure exerted on the bulb, B.
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When the pressure on B is released, a partial vacuum is created in A, so that VZcloses, and VI opens, thus refilling A. The auxiliary tube, A, permits the accurate measurement of the volume of liquid 'used. This tuhe which can be made from a test-tube may be ground to fit the flask as shown in the drawing, or may be merely inserted through a cork or rubber stopper. The ground joint or stopper should fit loosely enough to permit the entering of sufficient air to replace the liquid used. Valves V, and Vz may be made by melting down the endof a thin glass rod to form a bead of the desired size; this is inserted with emery dust and twisted to form a smooth seat. The rod is then cut off to the proper length, the valve is reinserted, and a small cross rod of glass is sealed to the end of the valve to hold it in place.
