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VII. Re-determination of the Mass of a Cubic Inch oj Distilled Water. 
By H. J. Chaney. 
Communicated by Sir G. Gabriel Stokes, Bart., F.R.S. 
Received February 4,—Read June 19, 1890,—Revised January 16, 1892. 
The evaluation of the mass of a cubic inch of distilled water, as at present accepted, 
was based on weighings made in 1798 by Sir G. Shuckburgh ( ; Phil. Trans./ 1798, 
p. 133) ; and on measurements made in 1821 by Captain Kater (‘ Phil. Trans./ 1821, 
pp. 316 and 326). Subsecpient researches however, particularly those in relation to 
the mass of a cubic decimetre, show that it is desirable to re-determine the mass of 
the cubic inch of distilled water. 
The result of Shuckburgh’s experiments was that the cubic inch of distilled water 
at the temperature of 66° Fahr., the barometer being at 29'74 inches, weighed 
252*422 grains, and this value as corrected by Captain Kater, became 252*458 grains 
at the temperature of 62° Fahr., the barometer being at 30 inches ; or in vacuo 
(t. = 62° Fahr.) the cubic inch of distilled water weighed 252*724 grains. This 
corrected value, 252*458 grains, has been adopted in various legislative enactments ;— 
for instance the Weights and Measures Act, 5 Geo. IV., c. 74, section 5 (1824), 
declared that “ a cubic inch of distilled water, weighed in air by brass weights, at the 
temperature of sixty-two degrees of Fahrenheit’s thermometer, the barometer being 
at thirty inches, is equal to two hundred and fifty-two grains and four hundred 
and fifty-eight thousandth parts of a grain, of which the imperial standard Troy 
pound contains five thousand seven hundred and sixty.” 
Owing to doubt as to the true mass of a cubic inch of distilled water, the above 
section of the Act of 1824 was repealed in 1878, and has not been re-enacted. No 
re-determination of the mass of a cubic inch of distilled water in terms of the present 
imperial pound has yet been made; the above value, 252*458 grains, being based 
on the old Troy pound of 1758. Dr. Wild’s investigations* appear indeed to 
show that later results obtained in the evaluation of a definite volume of distilled 
water, differ appreciably from those obtained in terms of the old Troy pound. If, for 
instance, the mass of a cubic decimetre of distilled water at 4° C., as originally 
determined by Lefevre-Gineau and Tralles in 1799, is taken as 1000*000 gnus. 
* ‘ Bericlit iiber die Arbeiten zur Reform der Schweizerischen Urmaasse,’ Ziiricb, 1868. 
2 U 2 4.7.92 
