378 Third Report of the Commissioners 



original, and bow far they deserved to be announced to the 

 world as such : but if such a publication could not be encouraged 

 without admitting the originality of other facts, which they sup- 

 posed to be known to every student of natural philosophy, they 

 had surely some reason to hesitate, before they gave it their un- 

 qualified approbation. 



vi. Third Report of the Commissioners appointed hj/ His Majesty 

 to consider the subject of Weights and Measures. 



Mav it please Yot'R Majesty, 



We, the commissioners appoinTed by your Majesty, for the purpose of 

 considpring the subject of weights and measures, have now completed 

 the examination of the standards wiiich we have thought it necessary to 

 compare. Tiie measurements which we liave lately performed, upon the 

 apparatus employed by the late Sir George Shnckburgh Evelyn, have 

 enabled us to determine, with sufficient precision, the weight of a given 

 bulk of water, with a view to the fixing the magnitude of the standard of 

 weight ; that of length being already determined by the experiments re- 

 lated in our former Reports ; and we have found by the computations, 

 whidi will be detailed in the Appendix, that the weight of a cubic inch of 

 distilled water, at 62° of Fahrenheit, is Q52.72 grains of the Parliamentary 

 standard pound of 1758, supposing it to be weighed in a vacuum. 



We beg leave therefore finally to recommend with all humility, to your 

 Majesty, the adoption of the regulations and modifications suggested in 

 our former Reports ; whicii are principally these : 



1. — That the parliamentary standard yard, made by Bird in 1760, be 

 henceforwards considered as the authentic legal standard of the British 

 empire ; and that it be identified by declaring, that 39.1393 inches of this 

 standard, at the temperature of 62° of Fahrenheit, have been found equal 

 to the length of a pendulum supposed to vibrate seconds in London, oh the 

 level of the sea, and in a vacuum. 



2. — Tiiat the parliamentary standard troy pound, according to the 

 two pound weight made in 1758, remain unaltered; and that 7000 troy 

 grains be declared to constitute an avoirdupois pound ; the cubic inch of 

 di.^tilled water being found to weigh at 62°, in a vacuum, 252.72 parliamen- 

 tary grains. 



3. — That the ale and corn gallon be restored to their original equality, 

 by taking for the statutable common gallon of the British empire, a mean 

 value, such that a gallon of common water may weigh 10 pounds avoirdu- 

 pois in ordinary rirnnnstances, its content being nearly 277.3 cubic inches ; 

 and that correct standards of thisimpciial gdllon, aud of the bushel, peck, 



