Discussion on “crest voltmeters” (Sharp and Doyle), “the crest voltmeter” (Chubb), “the voltmeter coil in testing transformers” (Hendricks), “notes on the measurement of high voltage” (work), New Yor

E. E. F. Creighton: The question of the measurement of high frequency is always important, and always will be important until all the problems relative to the protection of apparatus are solved. Dr. Sharp´s statement that the kenotron might be used for the measurement of high frequency is of the greatest importance. The dielectric spark lag of a perfect vacuum is practically infinite, because there are no ions present. Going down to a vacuum of something like fifteen millimeters in the usual gases the dielectric spark lag decreases to about the low value at atmospheric pressure.