97 



its apparent weight in air of a density different from that which it 

 has when #=65'66 Fahr., 6=2975 inches, a knowledge of the 

 volume of the lost standard is requisite. An indirect way of arriving 

 at it was suggested by Professor Schumacher, by an examination of 

 certain Parliamentary Reports, presented May 26, 1758, April 11, 

 1759, March 2, 1824. It appears from the first of these, that 

 Mr. Harris, then Assay Master of the Mint, presented to the Com- 

 mittee three troy pounds made under his direction, one of which was 

 the lost Imperial standard ; and from the third, that one of the two 

 remaining pounds came into the possession of Mr. Vandome, and 

 the second into the possession of Mr. Bingley of the Mint. Pro- 

 fessor Schumacher then observes that we can still either determine, 

 with the highest degree of probability, the density of the lost Im- 

 perial standard, or know with certainty that all hope to arrive at this 

 knowledge is lost. It will be only requisite to ascertain with the 

 greatest care the densities of both pounds, the one in the possession 

 of Mr. Bingley, the other in the possession of Mr. Vandome. If the 

 density of both is found the same, we might from that circumstance 

 draw the highly probable conclusion, that the three single pounds of 

 Mr. Harris, according to my hypothesis, were really made of the 

 same identical metal ; and the density of the two remaining pounds 

 might with safety be considered as that of the lost standard. If, on 

 the contrary, the two remaining pounds prove to be of different den- 

 sities, the hypothesis that all three were made of the same metal is 

 evidently erroneous ; and nothing can be inferred from the density of 

 either of the two remaining. 



Mr. Vandome readily consented to allow his troy pound to be 

 experimented upon by the Committee. Denoting this weight by 

 the letter V, by weighing in air and in water it was found that 

 AV=8'15084, and that it was about O'o09 grain lighter than U. 



Mr. Bingley had in his possession two troy pounds, both dated 

 1758. One of these, O, said to be the original weight from which 

 the standard was made for the House of Commons in 1758, has 

 since been purchased by the Committee ; the other, M, has been pre- 

 sented to the Mint by Mr. Bingley. As Mr. Bingley was unwilling 

 to permit either of these weights to be weighed in water, Messrs. 

 Troughton and Simms were commissioned to construct an instru- 

 ment on the principle of the Stereometer invented by M. Say for the 



