T 4° 
TlMEHRI. 
the waste products ; and, though they are seen above 
to possess considerable force-value, are not to be com- 
pared with the carbo-hydrates as dynamical agents. 
These latter are especially easy of digestion, and owing to 
their universality of occurrence and cheapness, form the 
diet most convenient for the performance of severe 
exertion. 
The figures given above represent the force-value of 
the principles in their pure form. Professor FRANKLAND 
has also determined the force-value of various articles of 
food in which they occur. A great number of them con- 
tain a considerable quantity of water, which of course, 
weight for weight, militates against their force-value. 
Force-value of i oz. of various articles of food. 
Force-Value 
Force-Value 
NAME OF FOOD. 
in 
NAME OF FOOD. 
in 
foot-pounds. 
foot-pounds. 
1. Fats 
Grape sugar 
284156 
Cod-liver oil 
789400 
Bread crumb 
186240 
Beef fat 
786100 
Potatoes 
86366 
Butter... 
629738 
3. Nitrogenous. 
2. JUixed but princi- 
Cheese... 
377802 
pally carbo-Jiydrates. 
Yolk of egg 
286524 
Oat-meal... 
340759 
White of egg 
49937 
Flour .. 
332572 
Ham ... 
145513 
Pea- meal 
327046 
Beef ... 
122614 
Arrowroot 
340122 
Veal ... 
101511 
Ground rice 
325614 
Mackerel 
139782 
Cane sugar 
290207 
Whiting 
68571 
These figures give the total force-value, but it must be 
remembered that wherever thermal energy is transformed 
into potential, in other words, wherever power is de- 
rived from heat, an enormous loss occurs. The more 
perfect the machine, the more complete is the transfor- 
mation of the heat into work ; but even in so perfect a 
