32 TrANTS ACTIONS OF THE ROYAL CANADIAN INSTITUTE 



(9) One definite problem along these latter lines, is the development 



of a precision electrical hygrometer. The writer has developed 

 electrical hygroscopes, based on the variable conductivity of thin 

 films of hygroscopic solutions exposed to the atmosphere, which 

 indicate changes in humidity of one hundredth of one per cent., 

 but owing to ignorance about the behaviour of the conflicting 

 factors, and the experimental difficulties involved in conductivity 

 measurements of this character, they have not yet been developed 

 further. 



Bibliography 



The bibliography dealing with these topics is very large and involves 

 nearly one hundred papers. The following articles by Leonard Hill 

 form an admirable introduction, present an almost complete survey, 

 and develope or initiate some of the most important contributions to the 

 subject. As they include also a very extensive list of references prac- 

 tically covering the whole ground, it is unnecessary to repeat again the 

 bibliography in full. 

 Hill, L. Griffith, O. W., and Flack, M. "The Measurement of the Rate 



of Heat-Loss at Body Temperatures by Convection, Radiation and 



Evaporation." Phil. Trans. Roy. Soc. Lon. B., vol. 207, pp. 



183-220. (1916.) 

 Hill, L. "Atmospheric Conditions which affect Health." Quar. Jour. 



Roy. Meteor. Soc. vol. 45, pp. 189-237. (1919). 

 Hill, L., and Hargood-Ash D. "On the Cooling and Evaporative Powers 



of the Atmosphere." Proc. Roy. Soc. Lon. B., vol. 90, pp. 438-447. 



(1919.) 

 Hill, L. "Science of Ventilation and Open Air Treatment." Report 



to Medical Research Committee for National Health Insurance 



(Pub. H. M. Stationery Office). 

 The reports and various papers under the auspices of the New York 

 State Commission on Ventilation, and those of the Chicago department 

 of Health, present the most recent American contributions to the subject, 

 and also give further useful references. The final analysis and the cor- 

 relation of these extensive investigations are eagerly awaited. Careful 

 reference should be made to the journals listed on page 4 and also 

 to the Monthly Weather Review for the past six years, as a very large 

 number of their articles have either a direct or an indirect bearing on 

 this work. 



The recently published text-books, "Manual of Meteorology," by 

 Sir Napier Shaw (Cambridge University Press), "Physics of the Air," by 

 W. J. Humphreys (Lippincott), and "The Principles of Aerography," 



