#Rhythmic changes in weather and in crops#.

A psychological movement, once started, accumulates force and momentum up to a certain point where a reaction begins.

This rhythmic movement as it appears in the capitalization of enterprises is favored and magnified, we have seen, by the wide use of credit and by the constantly changing technical and physical conditions of industry.

These call for constant revaluations of the sources of incomes, thus destroying customary and habitual valuations.

But why should the cycle begin or end at one point of time rather than at another; and what determines the length of the cycle?
Some of the new dynamic forces such as inventions and growth of population are distributed pretty regularly along the line, so that their influences are nearly equalized.