JOURNAL OF CHEMICAL EDUCATION

To the Editor: May I add the following remarks to the rerent paper

by Dr. C. D. Coryell "The periodic table: the 6ddf mixed transition group" (J. C a m . EDUC., 29, - -

62 ( i952)) . The so-called actinide hypothesis was first proposed

bv Dr. G. E. Villar of the Facultad de Ingenieria de ~ontevideo, Uruguay, as early as 1938 (BOY. Fac. Ing. Montevideo, 5 , 231 (1938); Chem. Abstracts 33, 2003-4 (1939)). Later he published detailed chemical, physi- cal, and crystallographic data supporting his actinide hypothesis (Ann. A d . Brasil. Sci., 12, 51 (1940); An. Ass. Quim. Argentina, 31, 213 (1943)). A short account of this hypothesis was also published in the United States (J. CHEM. EDUC., 19, 286 (1942)).

JULY. 1952 373

Villar's actinide hypothesis was confirmed by the brilliant researches of Seahorg and associates a t the University of California.

I should like to point out that Glockler and Popov (J. CHEM. EDUC., 28, 212 (1951)) were not the first to propose that the neutron may be included as the element of atomic number 0, as stated by Dr. Coryell. Although I have failed thus far to find the originator of the idea, many Brazilian and Spanish

chemlcal textbooks include this hypothesis. In 1949 Dr. E. Silva proposed not only to consider the neutron as the element of atomic number 0 but also to consider it as the first noble gas (SILVA, E., "Quimica inor- ganica," Recife, 1949).