ON CALORIMETRIC OBSERVATIONS ON MAN. 239 
figures have been obtained which fall into four groups corresponding 
to the grades of mechanical work done. It has been found that these 
results may be expressed by a constant multiplied by a function of 
the subject’s weight, which varies with the amount of mechanical 
work performed in the different groups, i.e. 02, ‘03, ‘O7 and ‘09 h.-p. 
Group A—Heat-production = K,W*" 
” B— ” — K,W** 
» O— 4 SSK WwW 
” D— ” — K, 
From these results it is evident that the weight becomes less and 
less of a handicap as the mechanical work increases. And, to carry 
this a stage further, the query arises as to the likelihood of the weight 
Ecoming a positive advantage at a still higher grade of mechanical 
work. 
The communication to the Physiological Society contains a formula 
for one of the subjects cycling at a revolution rate varying from 40 
to 98 revolutions per minute, and performing external work against a 
brake varying in different experiments from 0 to 73 calories per hour— 
4gVuai + 568 
we 
The first part of the formula represents the heat-production associated 
with the rate of movement ‘ V,’ and is the same no matter what the 
value of the external work performed by the movement. The second 
is the ‘ coefficient of efficiency ’ multiplied by the external work done, 
and fully represents the heat-production associated with the perform- 
ance of external work. It will be noticed that this coefficient of 
efficiency is represented as varying inversely with the two-thirds 
power of the subject’s weight, and that the ‘ efficiency ’ which is its 
reciprocal therefore varies directly with this value. This has been 
found universally the case in the data from all the remaining subjects, 
and explains the fact that in the heavier work experiments the results 
become independent of the subject’s weight, if consideration is paid 
to the other fact, also elicited from these data, that the heat-production 
associated with movements per se (irrespective of the mechanical work 
performed by them) varies, on the other hand, directly with the function 
of the weight. In fact the total energy transformation is the sum 
of the two factors, one due to the subject’s movements per se varying 
directly, the other due to performance of mechanical work in the 
course of these movements varying inversely as the subject’s weight ; 
but in neither case in a simple linear fashion. The general formula 
given (Proc. Physio. Soc., March 1914), is 
x work in Kals. per hour = Kals. per hour. 
» 566.8 
s7WV ER +i x work, 
The first fraction is probably expressible in the following form— 
KWV?? where ‘v’ is the natural rate due to the ‘ pendular 
character’ of the limb movements, and V is the particular rate 
imposed in each experiment. 
