PHYSICS: G. W. STEWART 
Proc. N. a. S. 
It is not necessary to carry the analysis farther, since neither theory 
would be benefitted by the fulfillment or non-fulfillment of these predic- 
tions. The question at issue is not met in this manner. It is involved 
in features lying outside the province of the present paper and is being 
treated by other authors, as mentioned above. 
^ Castle, W. E., (a) "Is the arrangement of the genes in the chromosome linear?" these 
Proceedings, 5 1919 (25-32); (b) "The linkage system of eight sex-linked characters 
in Drosophila virilis (data of Metz)," Ibid., 5 (32-36). 
2 Sturtevant, Bridges and Morgan, "The spatial relations of genes," Ibid., 5, 1919 
(168-173). 
3 Castle, W. B., "Are genes linear or non-linear in arrangement?" Ibid., 5, 1919 (500- 
506). 
* Metz, C. W., "The linkage of eight sex-linked characters in Drosophila virilis," 
Genetics, 3, 1918 (107-134). 
s See Metz and Bridges, these Proceedings, 3, 1917 (673-678). Before the hairy 
stock was lost some data on the value hairy-magenta were obtained by Weinstein, as 
noted by Muller (A ?ner. Nat., 54, p. 118), but the numbers were hardly large enough 
to be conclusive. 
8 Assuming, of course, that crossing-over is a consistent process, and that the experi- 
ments are conducted under similar conditions. 
7 My data, in the cases under consideration, include only relatively small numbers 
and give ratios of only approximate accuracy, as indicated in my paper. This fact 
alone would vitiate predictions of short distances (such as the first two) even if they were 
otherwise valid. 
THE FUNCTIONS OF INTENSITY AND PHASE IN THE 
BINAURAL LOCATION OF PURE TONES 
By G. W. Stkwart 
Physical Laboratory, State University of Iowa 
Communicated by R. A. Milhkan, February 5, 1920 
The permanence of the value of knowledge concerning the physical 
aspects of audition gives to contributions in this field a greater importance 
that is at first apparent. There has been much confusion as to the factors 
involved in the binaural location of sounds. An analysis of the problem 
of ascertaining the important factors and their relative values show 
that the solution will be secured most speedily by the separate control 
of these factors and by using first pure and then complex tones. This 
report includes experiments covering the frequency range of 100 to 1200 
d.v., the results giving the effects of intensity differences and phase differ- 
ences at the ears, each factor treated first alone and then in combination. 
Intensity. — Rayleigh {Phil. Mag., 13, 1907 (214)) was the first to point 
out that for frequencies of 128 and 256 d.v., the difference in intensity 
at the ears could not account for the ability to locate the source of sound. 
Although there have been many experimental contributions in the localiza- 
tion of sound, the only observers to make quantitative measurements of 
the effect of intensity were Hovda and the writer {Psych. Rev., 25, 1918, 
