Errors due to these variations are usually neglected though they may amount to three or four per cent in measurements claimed to be accurate to within one per cent. Assuming that an electroscope has been standardized at a given pressure and temperature, it is shown that the necessary calculations can be made once for all. From these calculations a chart is constructed by means of which the constant of the electroscope, corresponding to other values of the temperature and pressure, can be obtained graphically by a single reading.
O. C.. LESTER, "A RAPID AND ACCURATE METHOD OF CORRECTING MEASUREMENTS WITH EMANATION ELECTROSCOPES FOR ORDINARY CHANGES IN TEMPERATURE AND PRESSURE," J. Opt. Soc. Am. 11, 637-637 (1925)