380 On the Method of Assaying Silver. [No. 4, 



Assays can be confidently made by it to \ dwt. or about 6 

 grains in the pound Troy, or even indeed to half this, say to J 

 part (0.5) in 1000. 



The volumetric system is especially applicable where the silver 

 to be assayed by it is alloyed with copper only, and where the 

 fineness is approximately known beforehand ; both these condi- 

 tions to its successful usage exist in such Mints, where the only 

 silver assays made are those of metal already alligated for coinage 

 to the legal standard. 



It is acknowledged by its advocates that the presence of mer- 

 cury in the alloy would materially interfere with the accuracy of 

 the assay, and a certain (rather tedious) modification of the pro- 

 cess is essential to avoid error under such a contingency. 



Its adoption in the Indian Mints was not considered desirable 

 by their assay officers for reasons of which the following are a 

 few : — 1, A vast amount of the silver which comes to the Indian 

 Mints, (viz., China and Rangoon Sycee, bazaar cake silver, 

 Japanese coins, &c.,) contains not only mercury, but lead and other 

 coarse metals. 2, No sufficiently approximate idea of the fineness 

 of such silver can be formed before hand, thus necessitating a pre- 

 liminary assay by cupellation. 3, The high temperature of an 

 Indian climate renders it impossible to retain the solution of salt 

 at an uniform strength for any length of time ; the evaporation 

 and concentration derange the equivalence which it is essential to 

 maintain between it and the proportion of silver meant to be pre- 

 cipitated by it ; thus involving very frequent tedious testing to 

 ascertain daily the actual strength of the standard solution. 4, 

 The whole of the important manipulations should be gone through 

 by the Assay Master himself or his Deputy, a labour beyond their 

 strength in this climate with a very large daily number of assays 

 of various finenesses ; and one which would preclude the possibility 

 of his attending to the many other important duties which devolve 

 on the head of an Assay office to a Mint in India. 



The method of assay by cupellation then not being accurate 

 enough for the requirements of trade, and that by the French pro- 

 cess being considered unsuited to the peculiar work devolving on 

 the assay officers of the Mints in India (where there are no bullion 



