F. E. Nipher— Work done by a Muscle before exhaustion. 187 
The arm was lifted 2000 times without feeling any appreciable 
exhaustion. 
2. A weight w=050 ker. was lifted, as before, except that 
the weight was allowed to drop during the interval of rest, as 
in my earlier experiments. 
It was lifted 1500 times with very little of fatigue. 
According to (7) for complete exhaustion n= 440 
“ (6) « «“ n= 12000 
feet in one position, etc.). It would, however, be a dangerous 
pe iit 
xperiment 2 was also performed with a time t=1-164 (the 
time taken in my earlier experiments, reduced by Prof. Haugh- 
ton with the same result. 
This experiment also shows that eq. (2) does not represent 
this kind of work, for we deduce, from the chart, for the values 
of the constants 
21240 
(wah .n (wa)? 58 
making w=05, and we have (since a=1% and h=0°7) n= 
2500. The arm would be exhausted for 2500 lifts, which is 
hardly possible. pies 
nyone who will take the trouble to codrdinate the corre- 
sponding values of c and n’ as given in the first table, will 
see clearly that we were justified in retaining those values of 7, 
and only those, which we there reduced. Each curve, however, 
gives evidence of the fact, that for any weight, n varics as 
Some power of the strength. 
ee have made several series of experiments to investigate 
this point, determining the strength (s) of the muscle, by means 
¥ @ dynamometer. Calling 7, the time of exhaustion I have 
ound that he v 
tT=a(s—f)", 
Where » is a function of the weight, a and being also con- 
stant for the same weight. If the dynamometer really gave 
the absolute strength of the muscle, / would be equal to w. 
reclse values of these constants have not yet been obtained, 
ahd therefore decline to discuss this equation any farther at 
n 
St. Louis, Oct. 31, 1874, 
