294 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



nations of the same metal. In a special case at this end of the hall is 

 also exhibited a series of radio-active minerals and radium ores ac- 

 companied by a portrait and autograph of Mine. Curie. The excep- 

 tionally large and beautiful yellow masses of carnotite from Naturita, 

 Colo., were secured for the Museum from Mr. J. I. Mullen, by Mr. 

 F. L. Hess. This series is augmented by two large sections of fossil 

 logs impregnated with carnotite from Thompson Springs, Utah. 



The systematic metallic series begins in a row of floor upright cases 

 at the east end of the hall (pi. 16, fig. 2) . The collections are arranged 

 in the following order : Ores of gold, silver, silver lead, zinc, copper, 

 platinum, antimony, minor metals (including arsenic, bismuth, iridos- 

 mine, and cadmium), iron, mercury, aluminum, nickel, manganese, 

 and the minor metals used in steel manufacture (as tungsten, vana- 

 dium, titanium, and molybdenum). Among the gold ores are sam- 

 ples of the rich gold-bearing gravel from Dutch Flat, Placer County, 

 Calif., a large series of placer golds from Alaska, New Zealand, and 

 miscellaneous localities within the limits of the United States. 

 Among the silver ores, attention may be called to the nugget of native 

 silver, weighing 448 ounces, from near Globe, Ariz., and the dendritic 

 silvers from the region of Lake Superior. Also large ore masses 

 showing full width of the veins from the Reese River district, Nevada, 

 and the Enterprise mine, Rico district, Dolores County, Colo. As 

 with other metals, the exhibit is accompanied with a carefully se- 

 lected series showing the metalliferous minerals in their purity, and 

 the ore as mined in which the mineral is often so thoroughly dis- 

 guised as to be not recognizable. 



The silver lead ores — mainly galena — from world-wide sources are 

 selected to show all possible variations from the original native 

 sulphide through anglesite, cerusite, and impure ferruginous 

 varieties. 



The ores of lead, which are mainly galena, are of the same general 

 type. 



Ores of zinc are largely sulphides and their alteration products, 

 smithsonite and calamine. These are shown in all their varieties. 

 The unique deposit of silicate and oxide ores at Franklin, N. J., is 

 illustrated by fine large specimens showing zincite, willemite, and 

 franklinite, with their numerous accessories. As an adjunct to this 

 are two desk-top cases in front of the window containing selected 

 series of zinc ores and associated minerals and rocks from the 

 Franklin furnace and southwest Missouri regions. 



Ores of tin are shown from all the principal tin regions of the 

 world. These comprise a large series of the Straits tins and also of 

 those from the historical Cornwall mines, and stream tins and vein 

 ores from the numerous nonproclucing localities of the United States, 



