Tesla Effects

The cause of the innocuousness of these seems not to have been determined with certainty. If the impulses alternate at the rate of a million per second, it can easily be imagined that one of these would not have time in 1/1000100th of a second to produce a destructive effect on the tissues, and at the expiry of that minute interval an impulse operating in the opposite direction, and therefore tending to counteract the first, would follow, while its destructive tendency would, in turn, be neutralised by the third impulse, and so on. Analogous results occur in hearing, where, as the pitch of a note is gradually increased, it becomes more and more shrill till it reaches a certain rapidity of vibration which varies with individual hearers, and then the sensation of sound ceases entirely. On the other hand, it was lately maintained in a leading medical journal that the great potential, and not the high frequency, is the operating cause. As the potential is increased the quantity of electricity is diminished, and may at last become so small as to be too weak to injure the human frame. Mr. Harcourt will find much interesting information bearing on the lighting-up of an incandescent lamp on short circuit in Tesla's lecture on "Light and other High Frequency Phenomena," delivered before the Franklin Institute, Philadelphia, February, 1893, and before the National Electric Light Association, St. Louis, March, 1893.

A. T.