1818.] M. DuhameL 163 



warring elements of the political chaos arranged Or seemed to 

 arrange themselves, were all too sensible of the merit and useful- 

 ness of Duhamel to offer him much molestation. He accordingly 

 was nominated a member of the first class of the National Insti- 

 tute, retained his situation in the Corps des Mines, Was employed 

 as commissioner in the survey of many mining districts, both in 

 France and in the annexed provinces of Germany, and contri- 

 buted many useful papers to the Journal des Mines. In 1801 he 

 published a French and German dictionary of the technical 

 terms employed by the miners of each country. The approach- 

 ing feebleness of age, though it restrained his personal activity, 

 had no effect on his zeal and on his interest in the improvement 

 of that art to which he had devoted his youthful enthusiasm, his 

 manly energy, and his mature experience. With a temper 

 remarkably calm and placid, added to his other qualifications, 

 he engaged at first sight, and ever after retained the fond attach- 

 ment of his pupils ; as his years advanced, the appellation of 

 " Patriarch of the Miners " evinced the general respect in which 

 he continued to be held. A short illness, unaccompanied by 

 suffering, terminated his life at Paris on Feb. 20, 1816, in the 

 66th year of his age. 



The most important of his contributions to the Academie des 

 Sciences are the following: a memoir on the reduction of iron 

 ores, published in 177^ and another on the same subject in 

 1786. In these the information which he had previously ac- 

 quired in Bohemia and Styria is skilfully and successfully 

 applied, with certain modifications, to the treatment of the iron 

 ores of France. 



The Art of Liquation, published in 1788. This treatise is the 

 most complete account extant of the method of separating silver 

 from copper by means of lead. In this process the lead, being 

 melted with the copper, takes from it the greater part of the 

 silver, and is finally separated from the copper by exposing the 

 mixture to a temperature sufficient for the fusion of the lead, but 

 not of the copper. A multitude of minute particulars require 

 attention, in order that this process may be carried on to the 

 great t advantage ; and these are fully explained in the memoir 

 alluded to. It is true that this method is now becoming obso- 

 , even in those German establishments where it was carried 

 oh to a ^reat extent and with unrivalled skill, having been super- 

 d by the process of amalgamation; and, therefore, M. 

 Uuliamel's memoir is now chiefly valuable as a historical docu- 

 ni' ill. 



In the Journal des Mines his most useful memoirs are, on the 



1 methods of supporting shafts and galleries by timbering 



and walling; on the cupellation, or rather the refining of silver ; 



and on tin- separation of the earthy from the metallic parts of 



previous to fusion. 



l2 



