44 



JEtev. S. Haughton on the Law of Fatigue. [Nov. 18, 



raising and lowering the arms is constant, n is proportional to T, and the 

 law of fatigue gives the formula 



0+a) 2 n=A, (2) 



where A is an unknown constant. In the following Table I give the 

 values of w and the mean value of n for twenty distinct persons. The 

 time of lift is in all cases one second. 





Table I 



. Mean of Twenty Experiments. 





No. 



w. 



n (obs.). 



n (calc). 



Diff. 





lbs. 









1. 



2-56 



131-80 



128-0 



+ 3-8 



2. 



4-25 



87-55 



78-3 



+ 9-2 



3. 



5-87 



47*35 



53-5 



-6-2 



4. 



6-87 



40-25 



43-7 



-3-5 



5. 



7-75 



34-60 



37-1 



-2-5 



6. 



9-75 



27-15 



26-8 



+ 0-3 



7. 



14-00 



17-20 



15-4 



+ 1-8 



The column containing the calculated values of n was obtained from 

 equation (2) by using the values 



a=3-501bs., 

 A=4699. 



These values were obtained by finding the value of a, which renders 

 A most nearly a constant, or 



3A 



—r- = minimum. 



This Table gives 7 lbs. for the mean weight of the arm of all experi- 

 mented on, a result which accords with the known facts. 



In Table II. I give the results obtained from a single student, as 

 already described, each value of n being a mean of several experiments, 

 closely concurrent. 



Table II. Mr. Samuel Warren. 



No. 



w. 



n (obs.). 



n (calc). 



Diff. 





lbs. 









1. 



2-56 



140-0 



137-5 



+ 2-5 



2. 



4-25 



91-0 



86-4 



+ 4-6 



3. 



5-87 



63-0 



60-1 



+ 2-9 



4. 



6-87 



43-0 



49-0 



-6-0 



5. 



7-75 



40-0 



42-5 



-2-5 



6. 



9-75 



32-0 



31-0 



+i-o 



7. 



14-00 



18-5 



17-9 



+ 0-6 



