resumption of exchange professorship

548 CURRENT TOPICS. [J. F. I.

Resumption of Exchange Professorship.--The Karl Schurz Memorial Professorship in the University of Wisconsin was founded in IgIO , for exchange professorships with the German universities. The exchange was interrupted by" the war, but will be resumed in the coming academic year by lectures by Professor A. Sommerfeld, who holds the chair of Mathematical Physics in the University of Munich. Two courses will be given, one on Atomic Structure and the second either on the Analysis of Wave Propagation or on the General Theory of Relativity. The graduate school of the University also announces that Professor Svedberg of the University of Upsala will be present during the latter half of the academic year and will lecture and con- duct seminars in the fiekl of colloid chemistry. H . L .

The Removal of Small Amounts of Carbon Monoxide from Gas Streams by Passing Over Heated Granular Soda Lime. ROBERT E. WILsoN.--The problem of the complete removal of CO from gas streams is of importance in a number of industrial applica- tions. One or two German patents have mentioned the use of granular soda lime at fairly high temperatures for the purpose, but they offer no quantitative data. This paper describes a series of experiments at temperatures varying from 25 °0 to 55 o° C. and using soda limes of varying composition. The results show that high alkali soda limes give complete removal at the lowest temperature (around 35 °0 C.), providing water vapor was present and hydrogen absent. In the pres- ence of considerable amounts of hydrogen, removal is not complete under any conditions tried. The fundamental reaction involved is apparently :

CO + H,,O + NaOH - NazCO 3 + H~ (A. C. S. Abstract Service.)

Diffusion in Deformed Gels.mEzgir. HATSCI-IEK (Science Progress, I922, xvii, 86-94) has studied the diffusion of aqueous solutions of salts into deformed gels of gelatin. In one series of experiments, the gel contained lead acetate; when potassium chro- mate solution diffused into this gel, lead chromate (chrome yellow) was deposited in zones. In another series of experiments, the gel contained trisodium phosphate; when the solution of a calcium salt diffused into this gel, tricalcium phosphate was precipitated in zones. The shape and arrangement of these zones showed that it is highly improbable that the diffusion velocity varies with the varying degree of compression. Apparently the gel remains isotropic for diffusion under stress; and the velocity of diffusion is the same in a deformed ~'el as in an unstressed gel. . J . S . H .