SEPTEMBER, 1949
Such an organization would provide a place where teachers could send suggestions and ideas not significant enough for separate publication. Collections of these could be published from time to time with credit being given to their authors. In the same manner, examination questions thought by their authors to be original and significant enough to be of use to other teachers might be collected and published. It might be possible to enlist the services of the JOURNAL OF CHEMICAL EDUCATION to serve as the medium for the publication of such material. This is only the germ of an idea which I believe could be expanded into a cooperative system which would be of inestimable value to the teaching profession as well as to students of chemistry.
So1
Hiickel limiting equation holds very well for lower valence types up to about 0.2 p but is not adequate where high valence ions of opposite sign are involved and is not valid for nonaqueous solutions.
To the Editor: I have read with much interest the article on "A simple ketene generator" in the recent June issue. I would strongly recommend that a note of caution be passed on to any who might be inclined to make ketene. Wooster, Lushbaugh, and Redemann, of the FRED Y. HERRON University of Chicago Toxicity Laboratory and Department of Pathology, Chicago, Illinois, writing in the JourUNIVERSITYOF PITTSBURGH nal of Industrial Hygiene and Toxicol~gy, 29,56 (January, P ~ S B ~ PENNSYLVANIA GH, 1947), review the inhalation toxicity of ketene and of ketene dimer. This article should be required reading, To the Editor: in my opinion, before anyone uses ketene. Briefly, Professor Victor K. La Mer, of Columbia University, they show ketene to be a t least as toxic as phosgene, has been kind enough to point out an omission from and comparable in action. Ketene acts locally on the my recent paper, "The Debye-Hiickel theory and its upper respiratory tract causing deaths from pulmonapplication in the teaching of quantitative analysis," ary edema and the consequent anoxia in the same (THIS JOURNAL, 26, 280 (1949)). I failed to give manner as phosgene. Exposure to concentrations as deserved credit to the work of J. N. Bronsted, in the low as 0.2 mg./l. (116 p. p. m.) for ten minutes have development of the interionic attraction theory. It been fatal to laboratory animals. was Bronsted (J. Am. Chem. Soc., 44, 938 (1922)) who I suggest this reference be given at least as wide pubfist plotted the solubility of slightly soluble salts licity as the excellent article on the generator by Drs. against the square root of the concentrations of various Wang and Schueler. Ketene should be used with salts. Bronsted and La Mer (J. Am. Chem. Soc., extreme caution! 46, 555 (1924)) discuss the work of Debye and Hiickel and plot log f against 4and log S against 4. Bronsted (see Goldrnan and La Mer, J . Am. Chem. Soc., 51,2632 (1929)) also pointed out that the Debye-
