= 4.2;
= 0.000413;
= 0.000538, taking one second as the unit of time.
These results are represented by the curve 1 (Fig. V.). The logarithm of
is represented on axis of the ordinates, and the time on the axis of abscissas. One hour and a half after the beginning of the loss of activity the second exponential has become negligible with respect to the first in the expression for the value of