Current News and Notes - Another Tesla Discovery

Through the daily newspapers of Wednesday of this week Tesla announced another new discovery in electricity, which he says will require a large part of technical literature to be rewritten. The discovery is that capacity is not fixed and unalterable. In the announcement Tesla says he has found that capacity increases as the conducting surface is elevated in open space, from one-half to three-fourths of one per cent per each foot of elevation, though in buildings or near large structures this increase often amounted to 50 per cent per foot of elevation. Moreover, he says he has observed that there is a diurnal variation of the capacity, with a maximum during the day and a minimum during the night; and the astonishing statement is made that while both the sun and moon cause a slight increase in capacity, in the former case it is due to sunlight, but in the latter case not due to moonlight. Summing up, he says he finds that the variation of capacity is dependent upon the absolute height above sea level, though in a small degree; on the relative height of the conducting surface or capacity with respect to the bodies surrounding it; on the relative change of the circuit with respect to the sun, caused by diurnal rotation of the earth; and — on the distance of the earth from the sun! He considers it probable that instruments will be perfected for indicating the altitude of a place by means of a circuit properly constructed and arranged, and adds that he has thought of a number of uses to which this principle may be put. It is also said that inductance is seemingly modified by the same causes that tend to modify the capacity. Although no reference is made to the Pupin theory concerning the use of inductance in overcoming the disturbing effects of the capacity of telephone lines, the "discovery" appears to invalidate that theory.