101 



RS, assuming the density of U to have been the same as that of V, 

 T=5759"47141 grains, of which U contained 5760. By numerous 

 comparisons of the auxiliary weights with each other and with T, 

 A= 1239-88621, B= 1239-88604, C= 1239-88596, D= 1239-88579, 

 Q=0-64509. 



By 80 comparisons of PS with each of the weights T + Q + A, 

 T+Q+B, T + Q+C, and 100 of PS with T + Q + D, 



gr. t, b. 



PSt T + Q+A -0-002936 19'47 758'38 



PS: T + Q+B-0-001731 19'19 759-31 

 PS: T+Q+C -0-001621 18-83 754-38 

 PSii T+Q+D-0-000774 19-63 764-43 



Mean gr. 



-0-00177 19'28 759-12 



whence, supposing U to have the same density as V, 



PS = 7000-00090 grains, of which U contained 5760. 



Results of comparisons of PC No. 1, PC No. 2, PC No. 3, PC No. 4 



with PS : 



gr. No of Comparisons. 



PC No. 1 = PS + 0-00051 200 



PC No. 2=PS-0-00089 216 



PC No. 3= PS -0-00 178 204 



PC No. 4=PS-0-00316 204 



The weights Sp, Sb, K were returned to Professor Schumacher 

 accompanied by a weight V such that, by a mean of 200 compari- 

 sons, Sp + V:PS-0-00071 grain in air (#=13-1, J=759'09). 



By the good offices of M. Arago, permission was obtained from 

 the French Government to compare the new English weights with 

 the standard kilogramme of platinum, known as the kilogramme des 

 Archives, and which will be denoted by the letter U. The compa- 

 rison was made by two perfectly independent methods. In one of 

 these & was compared sixty times with PC No. 1 + PC No. 2 + 

 auxiliary weight B+ a platinum weight V of nearly 192*436 grains. 

 In the other, & was first compared 200 times with the platinum 

 kilogramme <, purchased for the British Government. 05 was after- 

 wards compared with PS + each of the four platinum copies of the 



VOL. VIII, L 



