The most important figures of these cycles are the following.
In the heroic cycles the Druids do not appear to have formed any corporation, nor do they seem to have been exempt from military service.
There are extensive manufactures, including those of motors and cycles with their accessories, also papermills, breweries, &c., and the population is largely industrial.
The pitch of a musical sound depends on the number of cycles passed through by the fluctuations of the pressure per unit of time; the loudness depends on the amount or the amplitude of the fluctuation in each cycle; the quality depends on the form or the nature of the fluctuation in each cycle.
This, of course, varies in different longitudes, while a further difficulty occurred in the attempt to fix the correct time of Easter by means of cycles of years, when the changes of the sun and moon more or less exactly repeat themselves.