Kohlrausch's Meter-Bridge

Abstract

MR. GLAZEBROOK, in commenting at the Physical Society on my use of Kohlrausch's meter-bridge with the telephone for the measurement of the resistance of the human body, suggested that the latter instrument was too sensitive, and that from self-induction perfect silence could not be obtained. Both these remarks are true; but if time and the chairman had permitted, I should have said that absolute silence is rarely got, but that the minimum of sound is so easy, after a little practice, to estimate, that onehundredth of a revolution on either side of it is instantly detected. The bridge wire takes ten turns on the barrel; consequently this amount is the thousandth part of a wire three metres long. Using a fixed resistance of 100^ω, the possible error is quite unimportant, and even with 1000^ω it is far within other instrumental accidents.