A simple method of correcting the weight of a body for the buoyancy of the atmosphere when the volume is unknown
John P. Cooke · American Journal of Science · 1883
It is a familiar fact, that, in the usual method of accurate weighing, the buoyancy of the atmosphere produces a sensible effect, whenever the volume of the load differs materially from that of the equipoise. But, as in all the ordinary processes of chemical analysis, the analyst deals solely with relative weights, the presence of a perfectly dry atmosphere does not influence his results, unless the conditions of temperature and pressure have changed between the successive weighings ; and even then the effect is insignificant in most cases. Still, when the volume of the vessel weighed is considerable, differing from that of the weights by as little even as twenty-five cubic centimeters (for example, in weighing the absorption tubes used in organic analysis ), the error caused by variations in the density of the atmosphere may be sufficient seriously to impair the accuracy of the result. In weighing large vessels ? as in determining the density of a gas ? the effect of any variation of buoyancy is eliminated by the well known methods of calculating the results; but the formulas usually given for that purpose involve as known quantities the volume of the vessel, the volume of the weights, the density of the air under the standard conditions, as well as the temperature and pressure at the time of the several observations; and, since the calculations are somewhat complex, and the required data not always readily obtained, the for mulas are seldom applied unless the volume of the load is quite large. Moreover, in these formulas the effect of each factor cannot readily