PROGRAM FOR THE MEETING OF THE DIVISION OF CHEMICAL EDUCATION OF THE AMERICAN CHEMICAL SOCIETY AT DALLAS, TEXAS, APRIL 18-21,1938 There will be two special features on the program at the Dallas meeting: a symposium on the Teaching of Elementary Organic Chemistry and a student program. The latter will consist of a number of papers and contributions by present students of chemistry and talks by well-known chemists on subjects of active student interest. Special efforts are being made to obtain a large student attendance a t the meeting, and the cooperation of all members of the Division is urged in this direction. N. W. F~IEESTRAW, Secretary
AN APPARATUS FOR DEMONSTRATING VAPOR PRESSURE WARREN R. SMITH AND GEORGE H. RIDGELY Lewis Institute, Chicago, Illinois
THE relations between vapor tension, vapor pressure, and boiling points are stumbling blocks for many students. To demonstrate these relations we have devised the apparatus shown. Its construction is not beyond the skill of the amateur glassblower. A and B are ordinary glass tubing partly filled with mercury. B has a sidearm G carrying the bulb F. D is heavy-walled rubber tubing long enough to allow the adjustment of levels of the mercuiy in A and B. C is
rubber tubing carrying a pinchcock E. The bulb F is partly filled with some liquid. (We have found ether convenient.) With the cock E open, A is raised until the mercury in B is level with the bottom of G. The liquid in F is boiled until all air has been driven out through C. While the liquid is still boiling the cock E is closed. A is lowered and B sealed a t H. I is resistance wire wound around B and kept warm enough to prevent condensation of liquid. The temperature of F is controlled by dipping i t in a beaker of water carrying a thermometer. This apparatus gives results sufficiently accurate for ordinary classroom and laboratory demonstration.
THE METAL CARBONYLS. IV. PROPERTIES-A CORRECTION Equation 1 on page 579 of this article [J. CHEM. EDUC.,14, 575-811 should read 1. Ni(C0)r hv --t Ni(C0)s CO On page 580 the first equation should read hv --t Fe(C0)4 f CO Fe(C0)a
+ +
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A CONVENIENT GAS ABSORBER PHILIP S. CHEN Nashville Agricultural Normal Institute, Madison College, Tennessee
A convenient gas absorber for making saturated solutions of sulfur dioxide, hydrogen sulfide, chlorine, etc., can be made from any ordinary Florence or volumetric flask as illustrated in the figure. The flask is filled with the solvent liquid to the neck and then tilted until the level of the liquid fills the lower part of the neck so that the air space in the flask is sealed. Gas is now allowed to pass through the solvent by means of a glass tubing slightly bent a t the lower end. Some of the advantages of this gas absorber are as follows. 1. The solvent liquid in the neck of the flask serves as a valve or check to prevent the gas from escaping. 2. The gas above the surface of the liquid is exposed to a largersurface than if the flask were not tilted, resulting in the larger amount of gas absorbed per unit time. 3. The absorption of the gas is further enhanced by the pressure created by the gas itself in the confined space above the liquid.
