82 REPORT ON NATIONAL MUSEUM, 1886. 



THE METALLURGICAL EXHLBIT. 



One of the largest exhibits in the Smithsonian collection at the ex- 

 position was that prepared under the direction of Mr. Fred P. Dewey, 

 curator of metallurgy and economic geology, who, with several assist- 

 ants, devoted his entire time, for several months prior to the exposition, 

 to the collection and arrangement of materials, James Temple Brown 

 being detailed to make a special collection of coals and articles illus- 

 trating the processes of coal mining. From Mr. Dewey's report the fol- 

 lowing account of the exhibit is taken : 



In the first division of this collection — that of economic geologyrr-it was designed 

 to exhibit collections illustrating the different kinds and grades of the ores of each 

 metal, and also a few collections of non-metallic minerals of economic importance. 



In the second division — that of metallurgy — it was designed to exhibit collections 

 representing the processes for the extraction of the metals from their ores by speci- 

 mens, where f)racticable, filling the gaps by means of illustrations and. descriptions, 

 and accompanying them by general illustrations and descriptions, so as to fully ex- 

 plain these processes. 



The ore collection was made up with a view to represent all the different varieties 

 of each ore and many of the most prominent mining regions. 



The Lake Superior copper region was very thoroughly represented, both on account 

 of the value of the mines, and as representing the kind of collections it is desirable for 

 the Museum to possess to illustrate a region or mine. The region was represented by 

 three prominent mines, showing three different and characteristic occurrences of the 

 ore. In the first place, the so-called mass mines, which are characterized by the occur- 

 rence of large masses of free copper, amounting in some cases to many tons of metal 

 in a single mass, were represented by the Central Mine. Mines of this kind also carry 

 considerable quantities of disseminated free copper. In the second place, the amygda- 

 loid mines, which are distinguished by the occurrence of free copper in amygdules, 

 bunches, strings, and sheets, from the size of a pin-point up to a few hundred pounds 

 in weight, disseminated iu a soft amygdaloid trap-rock, were represented by the 

 Osceola Mine. In the next place, the conglomerate mines, which are characterized by 

 the presence of free copper mostly in the form of strings in a hard conglomerate of 

 ferruginous quartz pebbles, were typified by the Conglomerate Mine. 



Taking the Conglomerate Mine as an example, the collection showed, first, the gen- 

 eral character of the ore and the inclosing wall rocks ; secondly, the occurrence of the 

 ore at various prominent points in the mine, which were accurately located ; and, 

 thirdly, a section of the rocks over a distance of G:U feet, by specimens taken at suita- 

 ble distances to illustrate the different characters and changes of the material. 



The collection in economic geology included placer gold, gold quartz, auriferous 

 gravel, auriferous pyrite, tellutide ores, iridium (iridosmine), native silver, wire sil- 

 ver, horn silver, ruby silver, base ores carrying silver, argentiferous lead ores, tin 

 ores, sulphide ores of antimony, cinnabar, sulphide ores of lead ; native copper, includ- 

 ing water-worn specimens ; mass copper, chips, amygdaloid and conglomerate dissem- 

 inated free metal, sulphides of iron and copper, oxides, oxidized ores of bismuth, sul- 

 phide ores of nickel and cobalt, five hundred specimens of iron ores showing all the 

 different kinds of iron ore found in the country, manganese ore, ores of zinc ; anthra- 

 cite, semi-bituminous, bituminous, splint, and cannel coal, and a large collection il- 

 lustrating the methods of coal mining, including large photographs (taken by elec- 

 tric light) of the interior of a coal mine, the firs t views of the kind ever produced ; 

 native sulphur, and iron pyrites. 



In making up the metallurgical collection it was not possible to exhibit the pro- 

 duction of each metal exhaustively, owing to the small amount of suitable material 

 previously in the department and the short space of time available for making new 



