ji6o Field Ml'skum or Natural Hihtoky - Reports. Vol. Ill 



ire m '• entire when it is I to open the case. 



Ti f the ty|>c already in u.>c in Hall 68. Before 



. oi i; • ns ihry were tarefull ' and any 



• '■ ' iial eliminated. The ^iii>:.ii j-i.m of in- 



'^r- -iously .. ' .T>».-.t u ^«; retained, the ore* 



in Ri . . t'T in : • s. As before, the 



'ip of mining districts have been placed together and for 



all such an individual label has been prepared. It may be 



said that most of the important mining districts of the precious metals 



of the world are n ted in this collection. The large specimens 



on the floor of the liall are grouped g* hically also as far as 



Specimens t<»o largo for these cuit^ were removed to V.r 



All of the specimens in Hall 72 arc now protected by 



glass. Mill, h better pf'-f^Mtion of them i*^ invu', ! •' m s.c 



hern : rto. In .1 11 to the large ^, 



ontain a number of special collections, such as those illustrat- 

 ing alloys of gold and silver, salvage of gold and silver waste, and 

 platinum ores from various parts of the world. Three floor cases 

 are also devoted to the metallurgy of the precious metals and lead. 

 In one of these is exhibited an ' itc German method of treating 

 ' - ! lead ores, the results u: tac difTcrent pr ' n- 



i;.,. . to show the course of treatment. -\ 1 ..us 



.^ of silver-lead ores in th'" .rlm.rv u........ occupies 



In order to make the n . m of the process 



snm#»what more graphic, this collection has been provulcd with .i 

 of a blast furnace. In this model, which was con.<:tructed in 

 the Department, the various features of the blast furnace are shown 

 in detail and a portion of the wall of the furnace is re* cd as 



^ • , rear so that the interior c" \ '^ 



' ' fa cyanide plant lor tr.i- t.\ r. u: gold 



.,,.» ,.t ....... t ;,, ..^., ...• »•,.. <1 . . "pjjg 



. .. .; with 



ns of • i in the 5 os. The 



: ; .: .,'5 shown in the model and a steam 

 pu i tine box are shown. A summar>* of the collections at pres- 



ent en I in the Hall and their distribution is as follow.«!: One 



1 ores. Canadian ores and Appala- 



: ».aic. lead ores of the Mi^ . Villey; 



-~ io ores; one ca^e Nevada. Montana. 



■•^. and r*^' Tes; one case. Califor- 



. New orc<; one case. Mex- 



