14 REPORT OF THE SECRETARY. 



Among other topics, the question of the effective ventilation of 

 buildings has been given attention, and initiative steps have been 

 taken to learn what investigators are making a serious study of this 

 important subject. The vitiation of the exterior atmosphere in 

 •closely settled localities is also recognized as a question of great im- 

 portance to the dwellers in cities, and an effort is making through the 

 publications of the Hodgkins fund to disseminate the results of late 

 noteworthy investigations in this connection. 



The application of atmospheric air to therapeutics has received 

 •consideration, and while no research having for its object the direct 

 use of the atmosphere as a curative agent has, as yet, been aided, the 

 work furthered by the fund, excepting that which deals almost ex- 

 clusively with the mechanics of the atmosphere, is closely related to 

 medicine and hygiene. Consequently the reports of investigations 

 and experiments prosecuted in widely separated localities, such as 

 London, South Africa, Paris, and the cities of our own country, 

 have been followed with interest, in common with all classes of 

 research which make broader the way for the practical utilization of 

 our knowledge of the nature and properties of atmospheric air for 

 the welfare of mankind. 



ABSOLUTE MEASURE OF SOUND. 



The research of Dr. A. G. Webster, of Clark University, on the 

 absolute measure of sound, which was aided again during the present 

 year by a moderate grant from the Hodgkins fund, is reported as 

 advancing satisfactorily toward completion. The instruments pre- 

 pared especially for use in this research are expected to prove of 

 service in solving many practical questions relating to sound, such, 

 for instance, as the testing of sound-proofing materials, or of audible 

 signals. In conducting the investigation many delicate points in the 

 theory of such instruments have been settled by actual experiment, 

 so that, in some particulars, the experimental knowledge is in advance 

 of the present mathematical theory. 



The manuscript describing the methods and results of this research 

 will be submitted to the Institution for publication when completed. 



PROPERTIES OF MATTER AT VERY LOW TEMPERATURES. 



The investigation of the properties of matter at very low tempera- 

 tures, involving the use of liquid air, in aid of which a grant was 

 approved in 1906, from the Hodgkins fund of the Institution on 

 behalf of Prof. E. L. Nichols, of Cornell University, has been 

 steadily progressing. The research is now to enter on a careful study 

 of the index of the refraction of gases, and gaseous mixtures and va- 

 pors, over extreme ranges of pressure of temperature. The effect on the 



