The difference in this case is that it is getting to be a pattern — increasing in frequency and violence.
The female is viviparous, and the young, which, unlike the parent, are provided with a long tail, live free in water; it was formerly believed from the frequency with which the legs and feet were attacked by this parasite that the embryo entered the skin directly from the water, but it has been shown by Fedschenko, and confirmed by Manson, Leiper and others, that the larva bores its way into the body of a Cyclops and there undergoes further development.
The two sets of figures show some corroborative features, notably the low frequency from 1860 to 1870.
The electric waves coming through space from the sending station strike against the receiving antenna and set up in it high frequency alternating electromotive forces.
By means of several adjusting screws the force and frequency of these blows can be exactly regulated.