new standards of weights and measures. ^ 



consider the degree of reliance which might be placed upon 

 the accuracy of the experiments made by Sir George Shuck- 

 burgh on this subject. 



A cube, a cylinder, and a sphere of brass were used in 

 these experiments ; and in consequence of some difficulties 

 which occurred, the weight of these, both in air and in dis- 

 tilled water, was so repeatedly ascertained by Sir George 

 Shuckburgh, as to leave no reasonable doubt of the accuracy 

 of his conclusions. But as the linear dimensions of the cube, 

 sphere and cylinder, might not have been determined with 

 equal precision, it was thought adviseable to repeat these 

 measurements. This was accordingly done ; and though in 

 detail they differed somewhat from Sir George Shuckburgh's 

 determinations, yet, fortunately, the variations were such as 

 nearly to counterbalance each other, and to occasion little 

 difference in the ultimate result, as may be seen in an account 

 of these last mentioned measurements given in the Philoso- 

 phical Transactions for 1821, 



Sir George Shuckburgh's results having been expressed 

 in terms derived from the mean of several standard Troy 

 weights, of one and of two pounds, kept at the House of 

 Commons, the Commissioners of Weights and Measures 

 thought it desirable that the Troy pound, which differed the 

 least from this mean, should be taken as the unit of weight ; 

 and therefore recommended that the Parliamentary Standard 

 Troy pound of 1758 should remain unaltered; and this has 

 been accordingly declared by the Legislature to be the ori- 

 ginal " unit, or only standard measure of weight, from which 

 all other weights shall be derived ;" and that it is to be 

 denominated '* the Imperial Standard Troy Pound." 



