Kohlrausch's “Physical Measurements”

Abstract

REPLYING to the letter of Mr. Nelson in NATURE of August 12, the value given for the κ in question in the ninth German edition of “Kohlrausch's Lehrbuch der praktischen Physik” (1901) is 0.457. But it must be borne in mind that this value is deduced on the assump tion that the specific gravity of the brass weights is 8.4, and seeing that the specific gravity of various samples of “brass” varies not inconsiderably, it is immaterial whether one uses 0.457 or 0.458 for the correction factor. The rounded value, 0.46, is near enough for most purposes, and that is the one given in the tables of Landolt-Birnstein. For accurate work the specific gravity of the weights must be determined in any case, and the value of κ calculated for these particular weights.