I. On a method of using the balance with great delicacy, and on its employment to determine the mean density of the Earth

Abstract

In the ease and certainty with which we can determine by the balance a relatively small difference between two large quantities, it probably excels all other scientific instruments. By the use of agate knife edges and planes, even ordinary chemical balances have been brought to such perfection that they will indicate one-millionth part of the weight in either pan, while the best bullion balances are still more accurate. The greatest degree of accuracy which has yet been attained was probably in Professor Miller’s weighings for the construction of the standard pound, and its comparison with the kilogramme, in which he found that the probable error of a single comparison of two kilogrammes, by Gauss’s method, was 1/14000000 part of a kilogramme. (“Phil. Trans.,” 1856.)