1870.] 377 



On the Method of Assaying Silver adopted in the Assay offices 

 of H. M. Indian Mints, by H. E. Bus teed, M. D., H. M. 

 Madras Army, Officiating Assay Master, Calcutta Mint. 



[with. pi. xvii.] 

 [Eead and received Sept 7th, 1870.] 



The process of assaying silver about to be considered is one 

 which (on a large scale, at least) is peculiar to the Indian Mints : 

 it has been in practice in the Calcutta Mint since 1850, it extended 

 thence in course of time to the Bombay Mint and more recently to 

 the Madras one. 



Though it has been favourably reported on, and described more 

 or less fully as an official duty by various assay officers to local 

 Mint Committees, &c, &c, no steps, that I am aware of, have yet 

 been taken towards making more public the manipulatary details 

 of the process. 



It has been suggested to me that it might prove not only in- 

 teresting, but useful to have described the practical working of a 

 system, of the utility of which great experience has been afforded 

 in the Indian Mints, as, on assays made by it, an amount of silver 

 bullion reaching on an average the value of over seven^ millions 

 sterling is annually purchased by these Mints, and by it a silver 

 coinage to about the same value annually, is watched over as re- 

 gards its purity and maintained up to the legal standard of fineness. 



I propose, therefore, to give a somewhat detailed account of the 

 process, omitting only the minor steps in the manipulations, which, 

 it would be unprofitably tedious to attempt to bring within the 

 compass of a description ; practice alone can lead to an acquaint- 

 ance, or can familiarize, with these. 



To render more intelligible to the general reader the nature and 

 object of this process of assay, and wherein it contrasts with the 

 other methods in more general use, it may be desirable in the first 

 place to allude briefly to the principles on which those other 

 systems depend for their results, avoiding technicalities and de- 

 tails, as a full description of those processes may be found in airy- 

 work on Assaying, and in most works of Chemistry and Metallurgy. 



# Average for last 20 years. 



