equivalent and thus measure the energy generated. What was the result?

Was the weight of muscle destroyed by ascending the Faulhorn or by
working on the treadmill sufficient to produce on combustion heat
enough when transformed into mechanical exercise to lift the body up
to the summit of the Faulhorn or to do the work on the treadmill?

Careful experiment had shown that this was so far from being the case
that the actual energy developed was twice as great as that which
could possibly be produced by the oxidation of the nitrogenous
constituents eliminated from the body during twenty-four hours. That
was to say, taking the amount of nitrogenous substance cast off from
the body, not only while the work was being done, but during
twenty-four hours, the mechanical effect capable of being produced by
the muscular tissue from which this cast-off material was derived
would only raise the body half way up the Faulhorn, or enable the
prisoner to work half his time on the treadmill. Hence it was clear
that Liebig's proposition was not true.

The nitrogenous constituents of the food did doubtless go to repair
the waste of muscle, which, like every other portion of the body,
needed renewal, while the function of the non-nitrogenous food was not
only to supply the animal heat, but also to furnish, by its oxidation,
the muscular energy of the body. We thus came to the conclusion that
it was the potential energy of the food which furnished the actual
energy of the body, expressed in terms either of heat or of mechanical
work.

But there was one other factor which came into play in this question
of mechanical energy, and must be taken into account; and this factor