PHILOSOPHICAL TRANSACTIONS. 



303 



VOL. LXXXVIII.] 



be 6.00745 inches; consequently the cube of this multiplied by .5236, gives 

 113.5194 cubic inches, for the solid contents of the sphere. 



Now the results of the several weighings of the cube and cylinder, both in air 

 and distilled water, as contained in the following synopsis. 



Contents (true to -^§^7) in inches 



Weight in air, true to 0.02 grain 



Weight in water, true to 0.10 grain 



Weight of an equal bulk of water, true ? 



to 0.12 grain, or l S6 ] o6 s j 



Weight of a cubic inch of water, from J 



these experiments j 



Cylinder. 



74.94826 



21560.05 

 2553.22 



19006.83 

 253.6C0* 



Therm. Barom. 



62° 



62 

 60.5 



Inches. 



29.00 

 29.47 



The weight of the sphere in air was 28722.42 grains; and the same in water 

 was 28673.51 grains; this divided by its content, 1 13.5 lg, gives 252.587 grains, 

 for the weight of a cubic inch of distilled water, by Mr. Trough ton's weights ;*j- 

 the barometer being 29.74, and the thermometer 66. 



Having, through the means of Mr. Whitehurst's observations, and of his own 

 instrument, ascertained the length of his proposed standard, in the latitude of 

 London, 1 1 3 feet above the level of the sea, under a density of the atmosphere 

 corresponding to 30 inches of the barometer, and 60° of the thermometer, which 

 is full as satisfactory, for all practical purposes, as if it had been done in vacuo, 

 which I conceive to be nearly impossible; and having determined the weight of any 

 given bulk of water, compared with this common measure; I believe it now only 

 remains, to ascertain the proportion of this common measure and weight, to the 

 commonly received measures and weights of this kingdom. The difference of the 

 length of the 2 pendulums, from Mr. Whitehurst's observations, appearing to be 

 59.89358 inches, on Mr. Troughton's scale; and a cubic inch of distilled water 

 in a known state of the atmosphere, having been found to weigh 252.587 Troy 

 grains, according to the weights of the same artist, it remains only to determine 

 the proportions of these weights and measures, to those that have been usually, or 



* The weight of a cubic inch of common or rain water has been reckoned about 253 grains, some- 

 times = 253.33 grains, at others 253.18. But authors do not seem to have agreed in what they meant 

 by common water, rainwater, pump water, spring water, and distilled water; for occasionally they are 

 all confounded, and made to pass for each other ; and sufficient notice seems not to have been taken of 

 the temperature to which these weights were assigned. — Orig. 



+ But, as will appear hereafter, these weights are too light, when compared with the standard in the 

 House of Commons, by about 1 in 1523.92; the correction therefore, for this difference, would be 



bs 0.165 grain, to be deducted from 252.587 grains. 



— .165 



And the weight of a cubic inch of distilled water, in grains of the parliamentary > __ „ 

 standard, will be j 



