324. F. FE. Nipher— Variation in the Strength of a Muscle. 
one may be capable of doing twice as much dynamical work as 
the other with a moderately light weight. This makes it 
necessary that such experiments should be made on trained 
muscles. 
It will be seen that Mr. Myers is considerably stronger than 
I, and that variations in the amount of work done are greater 
for him than for me. This means that variations in strength 
cause greater variations in the work done by bim than in my 
own case. This is entirely in harmony with the equation given 
at the close of my paper in this Journal, February, . 
uring the whole of this series of experiments the size of the 
muscles did not perceptibly change, while in Myers’ experi- 
ments the number of lifts with a5 ker. weight varied, in two 
successive experiments (Dec. “0 and 28) from 420 to 1,300. 
On the 29th of April, 1878, after a month of exceedingly 
severe mental work, I was present at a terrible accident, occa- 
sioned by the burning of a building. For a quarter of an hour 
was under severe mental strain and was for a week completely 
J. 
a-b on diagrams F, F and B, C. It will be observed that here, 
also, the observations with the dynamometer are most affected, 
ing the dynamical work of exhaustion. On days when from 
any cause the muscles are temporarily weak, the strength as 
or in other words, the work which a muscle can_ perform, 
depends not only upon its size, but also upon its quality. 
