Physics 533 



such as these, the Institution is discharging one of its most 

 useful functions by diffusing knowledge not easily accessible 

 among a large number of intelligent people who are gener- 

 ally cut off from original sources. 



The Report for 1894 includes several interesting papers 

 relating to electrical subjects. These include one on " Light 

 and Electricity," by Poincare ; another on "The Henry," by 

 Mendenhall ; and one on " The Age of Electricity," by Mascart, 

 together with Professor Rucker's address at the Oxford 

 meeting of the British Association for the Advancement of 

 Science, on " Terrestrial Magnetism." There is also an im- 

 portant paper, "On Atmospheric Electricity," by Professor 

 Arthur Schuster, in the Report for 1895. 



RADIANT ENERGY LIGHT AND HEAT 



IN 1855 there appeared as a part of Volume ix of the 

 "Contributions" a memoir by L. W. Meech, "On the Rel- 

 ative Intensity of the Heat and Light of the Sun upon 

 Different Latitudes of the Earth." A preliminary investiga- 

 tion, suggested by an inspection of monthly temperatures, had 

 been published in 1850 in the American Journal of Science. 

 The present investigation was intended to resolve the problem 

 of solar heat and light upon the single hypothesis that the 

 intensity of the sun's rays varies inversely as the square of the 

 distance. It is essentially a mathematical treatment on this 

 assumption, and an attempt is made to show that the conclu- 

 sions reached are in general accord with physical phenomena. 

 The effect of secular change in celestial constants is exam- 

 ined, and some interesting consequences are deduced. The 

 Smithsonian Reports during the several years following the 

 publication of Mr. Meech's memoir show that much interest 



