O'SHEA — ASrECTS OF MENTAL ECONOMY. 



195 



ing at midnight, going on the principle that one hour is as good 

 as another for study and the fresh morning hours are the best 

 for social pastimes. But practically all those who reported 

 testified that their minds worked best in the forenoon ; eighteen 

 reported being best in the afternoon, while two found they could 

 accomplish more at 5 o'clock in the morning than at any other 

 hour. The best hours ranged from 7 to 12 in the forenoon, 

 while the choicest period of the day is from 9 to 11. These 

 hours accord with investigations made by Lombard, although 

 his results are not by any means conclusive, since too few sub- 

 jects have been studied and disturbing factors such as the influ- 

 ence of alcohol, tobacco, and food, make his data in a measure 

 unreliable. Still his curve showing the rhythm of daily fatigue 

 is at least suggestive, and may be given here: 



8 & iQiiit i a j -^ s fe t e 9 to n ia i a s <+ s c. 



en — i — i — i — i — i — i — i ■■ T i — i — r ' r • — r— — i — i i T-i t^-t 



ZcO*. 



£00 



IfcC 



120 



■♦Ci 



Fig. 18. — Showing at each hour of the day and night how many centimeters 

 a weight of 3,000 grammes could be raised by repeated voluntary contrac- 

 tions of the forefinger before fatigue set in. The curve is highest at 10 to 

 11 a. M. and 10 to 11 p. m. Lowest 3 to 4 p. m. and 3 to 4 a. m. Circle with 

 dot observation made just after taking food ; square with dot smoking ;• 

 work done eight minutes after drinking fifteen cubic centimeters of whisky. 

 (Donaldson after Lombard.) 



There can be little doubt that for most people the morning 

 hours are the most profitable to be devoted to diligent, concen- 



