V O L U M E 20, NO. 10, O C T O B E R 1 9 4 8 ACKNOWLEDGMENT
The authors are indebted to Elizabeth Kummer for part of the experimental measurements. LITERATURE CITED
(1) Ballard, J. \I7., Oshry, H. I.,and Schrenk, H. H., J . Optical Soc. Am., 33, 667-75 (1943). (2) Ballard, J. W., Oshry, H. I., and Schrenk, H. H., U . S. Bur Mines. Rept. Invest. 3520 (June 1940). (3) Ballard, J. W., and Schrenk, H. H., I b i d . , 3888 (June 1946). (4) Brentano, J. C. XI.,Phil. -'dug., 6, 178-91 (1928). (5) Brentano, J.C. &I., Proc. P h y s . SOC.,47, 932-47 (1935). (6) Brindlry, G. 'S., Phil. Mag., 36, 347-69 (1945).
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16, 95-8 (1944). (10) Schafer, K., 2 . Krist., 99, 142-52 (1938). (11) Scheibe, G., "Chemische Spektralanalyse, physikalische Methoden der analytischen Chemie," F'ol. I, p. 108, Leipsig. Aksdemische T'erlagsgesellschaft,1933. (12) Taylor, A , , P h i l . Mug.,35, 632-9 (1944).
RECEIVED May 3, 1948. Presented before the First Congress of the Inter-
national
