250 REPORT OF NATIONAL MUSEUM, 1884. 



A small but interesting collection was obtained from the works of 

 E. Balbach & Son, Newark, £T. J., representing a combination of the 

 smelting process with the electrolytic process for the separation of 

 gold from copper. It contains various ores, together with the fuels and 

 fluxes, several mattes, the residue containing the gold from the electro- 

 lytic deposition of the copper, a very handsome sheet of the electrolytic 

 copper, and a small bar of the gold separated from the residues. 



To these collections representing the extraction of gold is added a 

 single illustration of its utilization. 



A collection showing the exceedingly minute and dedicate manipula- 

 tion required in the manufacture of gold leaf. This collection starts 

 with a sheet of gold as thin as it is convenient to produce by passing it 

 through rolls ; then the various steps in the process of reducing its 

 thickness by beating it with hammers between skins until the exceed- 

 ingly thin gold leaf of commerce is produced- This collection is pre- 

 sented by Hastings & Co., Philadelphia. 



It is very desirable to illustrate other processes of the utilization of 

 gold, and one of the first collections that we ought to have, and one that 

 it would not be very difficult to obtain, is an illustration of the manufact- 

 ure of gold coins. 



Iridium. — A small amount of the iridosmine, found on the northern 

 shores of California, shows the different sizes of grains of the material 

 as obtained. To this is added a small amount of the material as sepa- 

 rated from placer gold at the mint in purifying it for the manufacture 

 of gold coins. 



Silver. — A very large collection of the silver ores of Utah was ob- 

 tained. Part of the material was donated in exchange by Prof. J. E. 

 Clayton, of Salt Lake City, Utah, and was material that he had col- 

 lected from time to time, much of it such as could only be occasionally 

 obtained by a collector on the ground. The rest of the collection con- 

 sists of new material obtained at various mines near Salt Lake City 

 by Mr. Eeckhart. 



Some very handsome specimens showing the association of native 

 silver with native copper from the Lake Superior region mines were 

 presented by Capt. John Daniels, of the Osceola Mine. 



A good set of specimens showing the native silver with sulphide of 

 copper was obtained by the curator at Butte, Mont. 



There are a few localities producing beautiful specimens of native 

 silver that are not at present well represented in the Museum, and it 

 would be very desirable to strengthen the collections in this direction 

 by some further collecting, especially in the southwestern portion of 

 the country, which is not as thoroughly represented in the ore collec- 

 tion generally as it ought to be. 



The extraction of silver from its ores is represented by a large series 

 of collections, but more difficulty was encountered in getting full col- 

 lections, with the necessary information, in the case of silver than with 



