SCIENCE 



Friday, Mat 27, 1921 



On Acoustic Pressure and Acoustic Dilatation: 

 Professor Carl Barus 489 



American Association fo^r the Advancement of 

 Science : — 



Duty on Scientific Apparatus for Educa- 

 tional Institutions 494 



Scientific Events: — 



Science and the Printers' Strike; The 

 British Institute of Physics; The Boston 

 Meeting of the American Medical Associa- 

 tion; Mme. Curie's Visit to the United 



States 495 



Scientific Notes and News 498 



University and Educational News 499 



Discussion and Correspondence: — 



Frimiitive Notions of Light: Dr. Irwin (i. 

 Priest. A Section of the American Asso- 

 ciation on the History of Science: Profes- 

 sor Louis C. EIabpinski 499 



Scientific Boohs: — 

 Jelliooe on The Crisis of the Naval War: 

 Professor Alexander McAdie. Stevens 

 on Diseases of Economic Plants: Dr. Mel 

 T. Cook 501 



Special Articles: — 



The y -chromosome in Mammals: Dr. Theo- 

 PHiLUS S. Painter 503 



The Eochester Meeting of the Amevican Chem- 

 ical Society: Dr. Charles L. Parsons.. 504 



MSS. intended for publication and booka, etc., intended for 

 review should be sent to The Editor of Science, Garrison-on- 

 Budson, N. Y. 



ON ACOUSTIC PRESSURE AND 

 ACOUSTIC DILATATION 



1. Introductory. Apparatus. — On a number 

 of occasions, heretofore^ I have endeavored to 

 use the interferometer for the measurement of 

 Mayer and Dvorak's phenom.enon: but though 

 the experiments seemed to be well designed 

 and were made with care, they invariably re- 

 sulted in failures. The present method, how- 

 ever, has been successful and led to a variety 

 of results. 



The apparatus is shown in Fig. 1, where B 

 is a mercury manometer described elsewhere, 

 the displacements being read off by the com- 

 ponent rays LL' of the vertical interferometer. 

 The mercury of the U-tube is shown a.t m n tn', 

 above which are the glass plates g, g', the 

 former being hermetically sealed, the latter 

 loose, so that the air has free access. The 

 closed air chamber R above m, receives the 

 air waves from the plate of the telephone T 

 by means of the quill tubes t hermetically 

 sealed into the mouthpiece of the telephone, 

 and f sealed into the manometer. Finally t" 

 is a branch tube ending in a small stopcock 

 C or similar device at one end, while the 

 other communicates with tt'. Flexible rubber 

 tube connectors may be used at pleasure, so 

 long as the space bounded by the outer face 

 of the telephone plate, the mercury surface m 

 and the stopcock C is free from leaks. 



The cock C will eventually be replaced by 

 the glass tubes c and c' (enlarged) perforated 

 with minute orifices at at one end and open 

 at the other. 



The telephone is energized by two storage 

 cells and a small inductor with a mercury or 



1 Cam«gie Publ., No. 149, part III., pp. 206-08, 

 Washington, 1914, and subsequently. The phenom- 

 enon has been studied by Eayleigh, Kolacek, Lebe- 

 dew, Wien, Geigel and others. As to hydrodynamic 

 forces in pulsating media, the researches of 

 Bjerknes and W. Konig should be mentioned. 



