CHAP. XXIII. 



WEAR OF COltf. 169 



experiments conducted under the direction of a 

 committee of the privy council 1 between 1798 and 

 1802, by those eminent chemists Mr. Cavendish, 

 since deceased, and Charles Hatchett, Esq., who, 

 happily for himself and for all who know him, still 

 survives. 



The object of those experiments was not ex- 

 pressly for the purpose of ascertaining the loss on 

 gold by abrasion in a given space of time ; but to 

 ascertain what kinds of alloys and what proportion 

 of those several alloys formed the mixture of me- 

 tals which rendered them when coined into money 

 least liable to loss by abrasion. Mechanical con- 

 trivances were adopted for rubbing against each 

 other pieces of metal of different proportions and 

 kinds of alloys, and by comparison of their weights 

 before and after such rubbing, to determine which 

 description of them would form the metal least 

 subject to loss for the future coinage of Great 

 Britain. 



It was ascertained by the experiments of these 

 accurate and acute philosophers, that gold of the 

 finest quantity that could be used, viz. that con- 

 sisting of twenty-three parts and three quarters of 

 pure gold, and one quarter alloy, suffered a much 

 greater loss by friction than our standard gold of 

 twenty-two parts in twenty-four of pure gold, and 



1 These experiments are recorded in the Philosophical 

 Transactions for the year 1802, part first, page 160. 



