268 WORLD-POWER AND EVOLUTION 



of 1902 and 1904- W. F. Tyler, an English official interested in cli- 

 matology, secured the cooperation of a dozen persons "of normal 

 condition, regular habits, and equable temperament" whose occupa- 

 tions were such as to preclude rush and worry and to render the envi- 

 ronment of all days essentially the same. Each noon they were asked 

 to record their feelings according to a comfort scale in which zero 

 means perfect comfort, while 10 means that the heat is almost unbear- 

 able. His results appear in the following table. I have added column 

 E to show what temperature would correspond to each "hyther," or 

 degree on the scale of comfort, if the relative humidity remained 

 constant at 75 per cent. 



Tyler's experiments were conducted in weather so warm that no 

 days were perfectly comfortable for all his subjects. The humidity 

 made a great difference, however, as appears from the following table, 

 where the temperature is shown on the left and the relative humidity 

 at the top, while the hyther, or comfort vote, together with the number 

 of cases on which it is based, appears in the body of the table. 



