96 REPORT OF THE SECRETARY. 



showing selected types of ores as mined, but in which, as a rule, the metal or its 

 compounds are scarcely discernible. 



" In the series as exhibited attention is called, first, to the native gold — that is, the 

 gold found in the metallic state in nature, as displayed in the form of nuggets, leaf 

 gold, wire gold, and gold dust from various localities; second, to the compounds of 

 gold with silver, tellurium, autimony, and sulphur, as shown in the minerals pet- 

 zite, sylvauite, krennerite, and nagyagite; third, to the occurrence of the native 

 metal with its associates, either as dust or nuggets, in sand and gravel, or impreg- 

 nating quartz, slate, calcite, and other minerals forming the characteristic gangne, 

 and lastly, to the series of gold ores, representing the metal-bearing rocks as usually 

 mined and which, while, as above noted, show no trace, on casual inspection, of the 

 precious metal, nevertheless contain it in sufficient amount to render its extraction 

 by chemical or mechanical means a profitable industry. 



"The silver-bearing series is arranged in a similar manner. It is to be noted that 

 while gold is common in deposit of sand and gravel as placer gold, silver very 

 rarely occurs in this form, and is represented here only by the silver-bearing sand- 

 stone from Washington County, Utah. Native silver in the form of wire or moss 

 silver is, however, comparatively common, as shown in the specimens from Mexico 

 and Saxony. Some of the silver-bearing compounds are of great beauty, as illus- 

 trated in the ruby silvers proustite and pyrargyrite." 



In addition to the general series, a number of casts of exceptionally large and 

 interesting nuggets of gold and silver was arrayed in a separate case. Each cast 

 was accompanied by a descriptive label. 



In the windows were transparencies, showing an Australian coral reef and views 

 from the Mammoth Hot Springs, the Yosemite Valley, and the Devil's Tower, in 

 Wyoming. 



The specimens were selected and prepared by Prof. G. P. Merrill and installed by 

 Mr. W. H. Newhall. 



Department of minerals. — The exhibit of this department consisted of a series of 

 about five hundred specimens, selected and labeled to illustrate the several proper- 

 ties or characters of minerals. The general plan of arrangement will be understood 

 from the synopsis here presented. 



(1) Chemical mineralogy : Types of minerals. Variation in composition. Rela- 

 tion of water to composition. Relation of composition to physical properties. 



(2) Physical mineralogy : The crystal. The crystallographic axes. Crystal sys- 

 tems. Compound crystals. Imperfections of crystals. Crystalline aggregates. 

 Pleomorphs. Isomorphs. Pseudomorphs, (a) by substitution; (b) by deposition; 

 (c) by alteration. Cleavage. Fracture. Tenacity. Hardness. Color, (a) essential 

 color; (b) nonessential color; (c) varieties of color. Luster. Diaphaneity. 

 Fusibility. 



Special attention was paid to the order of arrangement. The several specimens 

 illustrating the chemical and physical properties of minerals were arranged to be 

 studied from left to right, beginning with the upper left-hand corner and regarding 

 each quadrant of the case as a unit. 



Chemical mineralogy, Avhich treats of those properties relating to chemical com- 

 position or atomic structure of a mineral and the chemical relations of the several 

 kinds of minerals, was illustrated by 184 specimens. Physical mineralogy, which 

 treats of those properties relating to form or molecular structure of a mineral and 

 the action of the various physical forces upon the several kinds of minerals, was 

 illustrated by 315 specimens. 



Department of ethnology. — The ethnological exhibit consisted of two parts: 



(1) An exhibit of the home life and industries of the Eskimo. 



(2) An exhibition of the domestic life and arts of the Pueblo region. 



In the first group the most conspicuous object was a house similar in construction 

 to those occupied by the natives of Norton Sound. 



This exhibit was prepared under the direction of Mr. E. W. Nelson, and was built 

 of logs set on end, the corner posts being the larger. Above these were placed 

 series of logs growing shorter with each layer, a square smoke hole being left at the 

 peak of the roof. The furniture of the house consisted of a bed made of driftwood, 

 of a fireplace on the floor with a curious device for directing the draft and smoke 



