The Pressure Errors of the “Challenger” Thermometers 1

Abstract

II. XI. Accurate Measurement of Great Pressures. IT will be obvious from what has been said, especially as regards the old apparatus which was carried about in the Challenger, that one of the most essential requisites of the whole investigation was the accurate measurement of pressure. All the ordinary forms of pressure-gauge were found to be untrustworthy. It was necessary that in all cases the pressure should be measured with certainty to about 1 per cent. No attempt was made to secure any greater degree of accuracy, as the indications of the thermo-. meters themselves could not in any case be trusted to less than 0°.1 Fahr.