June 9, 1899. ] 



SCIENCE. 



811 



ENERGY AT KECEIVER. 



The energy of the toae at the mouth of 

 the receiving resonator is proportional to 

 the square of the amplitude of vibration of 

 the sensitive plate. And since this plate 

 •carries one of the refractometer mirrors its 

 amplitude can be expressed in terms of 

 wave-lengths of monochromatic (sodium) 

 light. In short, an expression for relative 

 intensity will be : 



' B tan a 



I is tan a \ 



when B is the double amplitude due to the 

 motion of object glass, a is the slope of the 

 fringes due to tone, and w is the width of 

 a double fringe. This relative measure 

 can be reduced to absolute measure in a 

 manner diifering from that employed by 

 Wien* only in the fact that the energy of 

 the little mirror is taken account of and the 

 identical resonator in the identical position 

 but with plate of high pitch, is used to cale- 

 brate the sensitive arrangement in absolute 

 units. 



This combination of source and receiver 

 seems exceptionally well adapted to the 

 investigation of such problems as the vari- 

 -ation of the intensity of sound with dis- 

 tance, the viscosity of the air, sound 

 shadows, reflection of sound from various 

 substances, refraction of sound in various 

 jnedia, the distribution of sound in a room, 

 with the natural pitch and damping (echo) 

 of a room, intensity of the minimum sound 

 a,udible, test of Weber's Law,t etc. 



The elaboration of the instrument has left, 

 thus far, no opportunity for systematic 

 research. Some results of interest have 

 been obtained, such as tests for constancy 

 and sensitiveness, photographs of vowel 

 and other sounds ; but these results are 

 fragmentary, and have been of value chiefly 

 to serve the purpose of tests, and of sug- 



*Wiecl. Ann., 1889, p. 834. 



fFechner, ' llauptpunoteder Psychophyaik,' p. 185. 



gestion to I'urther improvements in means 

 or method. In the near future some 

 acoustical problems will be attacked in the 

 laboratory of Clark University, and the re- 

 sults, as well as a fuller account of instru- 

 ments and method, will be published, it is 

 planned, jointly by Professor Webster and 

 myself. 



Benjamin F. Shaepe. 

 Greexwicii, N. Y., June, 1899. 



NEW YORK STATE SCIENCE TEACHERS AS- 

 SOCIATION. 



The third annual meeting was held at 

 the Teachers College of Columbia Univer- 

 sity, December 29 and 30, 1898, affording 

 to the members of the Association an op- 

 portunity to attend most of the meetings 

 of the Society of Naturalists. 



Dr. Charles B. Davenport, of Harvard 

 University, read a paper on zoolog}^ as a 

 condition for admission to college. He 

 favored the study of animals by the labora- 

 tory method as outlined in the Harvard re- 

 quirements, and thought that too much at- 

 tention was being given to dissection in 

 most secondary schools. He encouraged 

 the study of economic zoology in a prepara- 

 tory course, leaving most of the dissection 

 to be done in the college. 



The first afternoon was devoted to the 

 report of the Committee of Nine, by Dr. Le 

 Roy C. Cooley, after which the Association 

 attended the annual discussion of the So- 

 ciety of Naturalists on 'Advances in Meth- 

 ods of Teaching.' In the evening the Presi- 

 dent, Dr. Charles W. Hargitt, delivered the 

 annual address, on ' Science and the New 

 Education,' in which he defined the relation 

 of science to the other elements of the mod- 

 ern curriculum. The address was followed 

 by a most enjoyable reception by the trus- 

 tees of Teachers College. 



The second day began with four simul- 

 taneous section meetings. Section A, Bi- 

 ology, in charge of Dr. Charles L. Bristol, 



