S. Haughton— Mechanical Work done by a Muscle. 187 
I have elsewhere* shown that the Law of er corresponds 
with other experiments based on different dat 
If we consider the useful work only, we ave from equa- 
tion (2), 
Aw 
Useful work=wn= ota)® (3) 
- equation represents a cuspidal cubic whose ordinate 
= as a maximum value, when w=a= half the weight of the 
The foregoing observations are = accordance with this de- 
duction, as may be seen from table 
TaBLE IL.—UseruL Work. 
No. w. wn (20 experimenters). 
1 2°50 lbs, 338 
2 5 372 
3 Sl 277 
4 6-S7- * 276 
5 76. > 268 
6 O75 264 
7 14°00 * 241 
Professor Nipher has published- two series of experiments, 
based on the principle of lifting different weights at a constant 
rate; and both series can be interpreted by means of equation 
(2), as I shall now show. 
He has published other experiments based on the principle 
of raising the same weight at varying rates: these — ments 
are not only abandoned by himself, but contain internal evi- 
dence of error; for both these reasons I shall abandon them, 
but I feel bound to pe rio: Professor Nipher’s first series at 
constant rates against his own repudiation, and as being, on 
Professor Hinrich’s oto at least quite as good as those 
last made by him. 
Professor Nipher’s experiments differ in two respects from 
those made by me, tables I, IL. 
1. Professor Nipher allowed a rest equal to the time of work, 
whereas in my experiments, the work was incessant, as the 
arm came down without velocity. 
2. From the mode of lifting the weights, there was a — 
- obability of other muscles assisting those intended to 
atigued. 
The first of these causes would refresh the muscles and ena- 
ble them to do more work than if not rested at all; and the 
second of these causes would bring in other muscles to their 
aid, and appear to make them do more than their proper work. 
* Principles of Animal Mechanics, London, 1873. 
