On the observed variations in the temperature coefficients of a precision balance

Introductory. -In a former paper communicated to the Royal Society, the apparent abnormal behaviour of certain precision balances was described and discussed. One of the most important points therein considered and discussed. One of the most important points therein considered was that dealing with the displacement of the resting-point, R. P., of a beam, consequent upon a uniform rise or fall in the temperature of the instrument. The magnitude of the displacement of the resting-point, R. P., for a change of 1°C. was termed thetemperature coefficient of a balance . The variations in the R. Ps. of the balances tested were observed within a somewhat limited range of temperature only. Within those limits they were found to be regular and expressible by an equation of the form Rt = Rs {1±αt ±βt 2 }, in which Rs and Rt are the R. Ps . at some standard temperature and t° respectively, andα andβ experimentally determined constants for a given balance and particular load.