ON CALORIMETRIC OBSERVATIONS ON MAN. 289 
retention of a uniform rate of movement throughout the whole series 
of experiments, as in the following cases :— 
Total Moo eee ~ Energy in Kals Current aeenkatel Number 
can am J, B, E.S.D. "De Cee eee ee 
Weight=55'8 K | Weight—62°0 K | Weight=61'8 K Amperes | *” Kals per! yinute 
Height=168 em.| Height=170 em.|} Height=165 cm. hour 
ae 125 149 — 0 ? 60 
2 167 187 185 cul ‘3 13 60 
3 212 - — 15 26 60 
4 244 265 — 18 34°5 60 
| 5 286 308 305 2°1 42°5 60 
The figures given in this table for the mechanical work performed 
upon the cycle are taken from the results of a series of calibration 
experiments performed upon the cycle ergometer by Mr. Crapper and 
his assistant, Mr. Bisset, in the department of electro-technics in 
Sheffield University, and I have to acknowledge the great obligation 
which I am under for their extensive assistance. In these experiments 
the cycle was driven by a specially convenient motor at the various 
speeds used by my subjects when cycling, and with a range of electrical 
currents in its eddy-current brake similar to that adopted in my 
experiments. Two sets of these calibration experiments were per- 
formed, one prior to and the other later than the bulk of the calorimeter 
experiments, and there was a definite difference between the two 
probably attributable to the difference of temperature at these widely 
separated dates. Unaware of the necessary temperature-coefficient, I 
have taken the figures from the later set (lower values), since this 
coincides better with the dates of, and temperatures prevalent at, the 
experiments given in the Table. It should be understood, therefore, 
that the figures given for the mechanical work performed on the cycle 
are, if anything, under-estimated both from this cause and from the 
nature of the method used in calibration. This is a point of importance, 
since an under-estimation of the mechanical work performed entails an 
under-estimation of the corresponding ‘ efficiency.’ 
Now, referring to lines 2 and 5 in the table, it will be seen that 
in the three subjects an increment in work-performance of 29°5 kals 
per hour (from 18 kals in line 2 to 42°5 kals in line 5) has led to the 
following increments in the total transformation of energy :— 
Tibboment ot Increment in Total Transformation of Energy 
Mechanical Work 
E. J.B. E. 8. D. | Dr. C. 
29°5 119 ° 121 120 
(286-167) (308-187) (305-185) . 
1912. U 
