178 BELL SYSTEM TECHNICAL JOURNAL 



primary rays and the other with a slightK' lower frequency, was 

 mentioned in that article; he has since published an account of a 

 series of nieiisurements made, not on the wave-length but on the 

 absorption-coefficient (in various substances) of the scattered rays, 

 and finds it altered from that of the primary rays in the sense and 

 more or less in the magnitude to be expected from the wave-length 

 measurements of the lower-frequency rays. The largest alterations 

 and the best agreements with theory are obtained with light atoms 

 and high-frequency rays. In the frequency-range of the visible 

 spectrum, the scattered ray of lowered frequency, sought for by P. A. 

 Ross in light of the wave-length 54{)1.\ scattered by mercury vapor, 

 is altogether lacking. The transparency of krypton and .xenon atoms 

 to slow electrons, discovered by Minkowski and Sponer, has been 

 confirmed by Ramsauer with his original (and better) method. The 

 transparency of argon atoms has also been \'erified by O. \V. Rich- 

 ardson and R. N. Chaudhuri, by a method sutliciently different from 

 the others to rank as an inde[)(.'ndent test. 



RKKKRE.NCES 



O. von Baeyer, O. lluliii, .ind 1.. Miitner: Phys. ZS, //, pp. ■t8S-4W (1910;; I2. 

 pp. 273-279 (1911). 



P. M. S. Blackctt: Pror. Roy. Soc. W2.\. pp. 1-17 i 1922). 

 L. de Broglie: Jour, tic Phys. (,S) 6, pp. lOl-lOS (1916). 



M. de Broglie: Jour, de Phys. (6) 2, pp. 265-267 (1921); C. R. 173, 172 (1922). 

 J. Chadwick: Phil. Mag. 40, pp. 734-746 (1920). 

 A. H. Compton: Phil. Mag. 46, pp. 897-9U (1923). 

 J. Danysz: Le Radium p, pp. 1-6 (1912); 10, pp. 4-6 (1913). 



C. Davisson, C. H. Kunsman: Science, November 25, 1921 and later issues; Phys. 

 Rev. 21. pp. 637-649 (1923); Phys. Rev. 22, pp. 242-25X (1923). 

 C. D. Ellis: Proc. Roy. Soc. toiA, pp. 1-17 (1922). 

 H. Geigerand E. Marsden: Phil. Mag. 25, pp. 604-623 (1913). 

 W. D. Harkins and R. D. Ryan: Jour. \\w. Chem. Soc. 4S, pp. 2095-2107 (1923i. 

 L. Meitner: ZS. f. Phys. //, pp. 54-66 (1923). 

 C. Ramsauer: Ann. d. Phys. 72, pp. .H5-352 (1923). 



O. VV. Richardson, R. N. Chaudhuri: Phil. Mag. 4$, pp. 337-352, and 46, pp. 461- 

 472, 553-564 (1923). 



P. A. Ross: Phys. Rev. 22, pp. 201-202 (1923). (Scallcring of light.) 

 P. A. Ro.ss: Phys. Res-. 22, pp. ,221-225 (1923). (X-ray spectra.) 

 E. Rutherford: Phil. Mag. 2/, pp. 669-688 (1911). (Deflection of charged par- 

 ticles bv atom-nuclei.) 



E. Rutherford and H. Robinson: Phil. Mag. 2(5. pp. 717-729 (1913). 

 H. U. .Smyth: Proc. Roy. Soc. /02.I, pp. 283-293 (1922-23); /o.;.!, pp. 121-134 (1923)- 

 G. VVentzel: Phys. ZS, '2.5, pp. 435-436 (1922). Ann. d. Phys. 6() (1922). 

 R. VVhiddington: Phil. M.ig. ./,?, pp. 1116-1126 (1922i. 

 C. T. R. Wilson: Proc. Roy. Soc. /o/.4, pp. 192-212; 1923. 



