J. B. Polya University of Tasmania

Hobart, Australia I A Semimicro Kipp Apparatus

A rapidly assembled, charged, and cleaned semimicro Kipp apparatus can he made by fusion of the irregular T-tube A and the pipetrshaped tnbe c as shown in the drawing. The dimensions are not critical hut thme suggested will be found to have some practical advantages in handling or cleaning the apparatus. Chips of iron sulfide or marble are intrn- duced through b into the compartment a; gentle rotation and tapping of A helps to distribute the material evenly. The out,let d is joined t,o the wash- t,nbe C a t e; the arrow jrepresents a suitahle connecting

tube with t,ap, spring, or screw clip. The compartment i wit,h the glass spiral is filled to a height of ' / r l / x in; glass wool may be placed in the bulb of C . Very fine control of the gas stream is possible through a second tap or clip in the connection between C and D. C may be calibrated as a bubble-counting flowmeter.

The t,histle funnel B ic pro~ided with a device to break t,he rapid flow of acid which surges upward when the exit d is closed. A set of short glass tubes in compart,ment g and a plug of glass wool h allow safe operation without increasing the length or complexity of the apparat,us. A large funnel, covered by a watch glass to minimize acid splashes, may be used instead, if a less compact construction is accept,able.

The gas-generator, the att,ached wash-tube, and the reaction ressel (e.g., a second tube like C replacing D, then leading to a third tube charged with alkali) are held in a Fieser filter block.' A single block can hold, say, three gas generat,ing trains, one each for carbon dioxide, chlorine, and hydrogen sulfide. The apparatus delivers 2000-4000 ml gas. It has been used with good results in classes of 15-20 students to one generator. Other generatorsz, %re preferred for work necessitating protracted delivery under relatively high pressure. The apparatus described in this note has advantages when the safe delivery of a very small amount (e.g., 1-5 bubbles of gas) is required.

The technical assistance of W. P. U. Dixon and J. Lemm is acknowledged.

I FIESEE, LOUIS F., experiment^ in Organic Chemistry," 3rd ed., D. C. Heath and Co., Boston, 1955, p. 3. ' HOLNESS, H., "Inorganic Qualitative Analysis, SemiMicro

Methods," Pitman, London, 1954, p. 11. a LIDSTONE, A. G., WILSON, C. L., AND WILSON, D. W.,

Metallwgia, 35, 171 (1947).

Volume 39, Number 6, June 1962 / 295