If On Assaying Silver. [ApRit 



ported value of silver, as ascertained by this method of assay* 

 approaches sufficiently near its true value for the purposes of 

 coinage and commerce. The practical assayer, however, does 

 not depend entirely upon this check : he attends particularly 

 to the fire ; regulates the temperature of the furnace ; 

 observes the appearances of the assays as they are work- 

 ing off ; allows no minutiae to escape notice during the 

 influential part of the process, which may be about 20 or 30 

 minutes, and what he thus observes, enables him to report 

 more correctly than he otherwise would be able to do from 

 the simple weight of the assay button. 



11. It is clear from these observations that the assay by 

 fire cannot be depended on as giving great precision of re- 

 sult ; its general accuracy may be stated relatively as one to 

 400 : — or about i per cent. The following table will shew, 

 however, that this limit is exceeded even by the first assay- 

 ers of Europe. I omit the names of the assayers as they are 

 not essential, remarking only that the samples of bullion sent 

 to them to be assayed, were sent by the French Commission 

 appointed to report on the new process of assay by nitric acid. 



1 VlLLES. 



Titres trouves aux alliage 

 mathematics de 



Observations. 



950 Mill. 



900 Mill. 



800 Mill 





Vienne .... 

 Madrid. . . . 



Idem 



Londres . . . 



Amsterdam. 

 Utrecht. . . . 

 Naples 



946.20 

 944.40 

 944.40 

 948.25 

 933.33 

 947.00 

 945.00 

 945.00 

 941.00 

 946 if 

 942 | 



898.40 

 893.70 

 893,70 

 896.25 

 883.50 

 895.00 

 896.50 

 891.00 

 891.00 

 897 \\ 

 894.00 



795.10 

 789.20 

 788.60 

 794.25 

 783.33 

 795.00 

 799.00 

 787.00 

 791.00 

 798 |4 

 790.00 



Sans compensation. 



Hambourg. . 

 Altona. 





12. This table exhibits full proof of the defect I have 

 been speaking of. The specimens of silver sent for assay, 

 contained respectively 950., — 900, and 800 parts of pure silver 

 in 1,000 parts, yet none of the assayers report them so fine, 



