THE UTILIZATION OF ENERGY. 513 
A comparison of these figures, expressing the total metabolism 
in its mechanical equivalent, is as follows: 
Per Kg. Mass and Meter. 
Speed 
arin Total Cc ted 
ADE: 9 ompure: Percentage 
Metabolism. Work : 
Graco ometard: Gian are Efficiency. 
78.00 138.4 49.14 35.5 
90.16 155.8 54.54 35.00 
98.11 167.0 58.40 34.97 
This computation gives an efficiency slightly greater than that 
obtained for the ascent of a grade without load, and in so far tends 
to confirm our conjecture, but the basis on which the work of loco- 
motion is computed can hardly be regarded as sufficiently accurate 
to give this result the force of a demonstration. 
The work of draft appears to be performed considerably less 
economically than that of ascent gr locomotion. Thus, for the 
horse, the efficiency for nearly horizontal draft was found to be 31.3 
per cent. at a walk, and in one experiment at a trot 31.7 per cent., as 
against 34-36 per cent. for ascent. In two other experiments at a 
trot, in which the work may have been excessive, a much lower 
efficiency was found, viz., 23.4 per cent. For draft up a grade of 
8.5 per cent. at a walk the efficiency was greatly reduced, viz., to 
22.7 per cent. The above figures refer to the work of draft only, 
after deducting the energy required for locomotion and ascent. A 
similar difference was likewise observed with the dog (p. 502), the 
efficiency in nearly horizontal draft being 28.8 per cent. as compared 
with 30.7 per cent. for work of ascent. 
Experiments on man, not cited in the above pages, in which 
the work was performed by turning a crank, have shown decidedly 
lower figures for the percentage utilization. 
Sprep anp Gart.—The energy expended by the horse in loco- 
motion at a walk was found to increase with the speed at the 
rate of 0.00334 cal. per meter and kilogram mass for each in- 
crease of 1 meter in the speed per minute. Kellner’s mechanical 
analysis of the work of locomotion mentioned above divides it 
into two parts, viz., that expended in lifting the body of the 
