Tour the National Museum After the First Fifty Years

[national museum south west range] Welcome to the South West Range of the National Museum

Collections in Metallurgy and Economic Geology

GOLD

--Placer gold, gold quartz, auriferous gravel, auriferous pyrite, telluride ores. In the case of California there is some of the first gold taken out by Captain Marshall on the 19th of January, 1848. The fact that these specimens were collected so long ago, and that the date of collection is known, adds very greatly to their value. It would be impossible to duplicate many of them.

A very fine collection from the North Bloomfield mine, Nevada County, California, represents the average of the rock as it is washed down by the little giant; the mercury used to catch the gold in the riffles; the amalgam as it is collected in the riffle-boxes; the purified amalgam, and the gold produced from retorting the amalgam; fine gold, and coarse nuggets of gold that are picked up off the floor of the mine at the cleanup. To this series is added a collection showing the heavy minerals associated with the gold which are taken out from the riffle-boxes with the amalgam. This is an exceedingly interesting and valuable collection illustrating as it does not only the extraction of gold, but also as illustrating a process which is without doubt the most economical of any mining process carried on anywhere.

Another collection illustrates the extraction of free gold from auriferous pyrite by stamping the material and collecting the gold, as an amalgam on copper plates. This shows the ore as received at the mill, which consists of a mixture of iron and copper pyrite disseminated through quartz (the gold occurs in the pyrites); the crushed material as it is passed through the sieves of the stamps; the battery pulp; the gold amalgam as scraped from the copper plates; the gold resulting from the retorting of the amalgam; the concentrations obtained by allowing the heavy portion of the material to settle out in running water, consisting of pyrite and calcopyrite and containing a very considerable amount of gold; and the sand or waste material.

A collection showing the exceedingly minute and delicate manipulation required in the manufacture of gold leaf. This collection starts with a sheet of gold as thin as it is convenient to produce it by passing through rolls; then the various steps in the process of reducing its thickness by beating it with hammers between skins until the exceedingly thin gold leaf of commerce is produced.

SILVER

--Native with native copper, native on sulphide of copper, wire silver, native and horn silver, ruby, base ores carrying silver, argentiferous lead ores.

The treatment of base ores, that is, ores carrying lead and copper, by roasting with salt (chloridizing) and stamping and amalgamating is illustrated by three collections.

TIN

--It has been generally supposed that tin was a rare metal in this country. This, however, is only partially true, the occurrence of cassiterite, the binoxide of tin, in small quantities, being known to mineralogists from a large extent of territory for many years; but it is only in very rare instances that this occurrence gave even the slightest evidence of there being a deposit which would prove of any commercial value. The first discovery that was at all favorable was made by Professor Jackson in New Hampshire in 1840. Specimens of this ore, together with a bar of tin produced, are in the Museum.

A small amount of cassiterite from two localities, together with a bar of the tin produced, from Montana, is exhibited. An ore of a different character, being a stanniferous wolfram, has been known in California for many years, and at one time quite extensive Operations were commenced upon the deposit. There are several specimens of this ore, together with two full-sized pigs of tin produced and several sheets of tin-plate. The next discovery of any importance was at Winslow, in Maine. In 1882-83, there were discoveries of tin in three widely separated localities, in Alabama, Virginia Dakota, and North Carolina, which have given promise of ultimately producing more or less tin. Specimens of all these are shown.

COPPER

--Native from Lake Superior region. Sulphide ores, oxidized ores. A very complete illustration of some of the uses of copper presented. This series includes specimens representing the rolling of copper into various commercial shapes, the manufacture of various styles of sheet metal with copper for a basis, the manufacture and utilization of brass in various forms, and the manufacture of copper and brass wire. The collections illustrating copper and brass are the most full and complete in the Museum.

NICKEL AND COBALT

--Sulphide ores from Pennsylvania and Missouri. To these are added a full series of the beautifully colored salts of the two metals, the metals as prepared for electroplating and illustrations of the plating; the whole forming a most attractive exhibit.

IRON

--The great collection made for the Tenth Census showing all the different kinds and varieties of iron ore found in this country.

A very extensive and valuable series of tests of the mechanical properties of the Fagersta steel made by Kirkaldy, of London. This is by far the most complete series of tests ever made, and the records in regard to the tests are full and complete, so that it is still a standard of reference.

Two interesting collections representing the manufacture of horse-shoes by machinery, giving the various styles and sizes adapted for different uses. A large collection of the different sizes and kinds of tacks.

ZINC

--Silicate, carbonate, and sulphide ores. Franklinite, zincite, willenite, and calamine.

Systematic illustrations of metallurgical operations, beginning with the ore as mined Andy continuing with each step in its preparation for smelting, are shown, together with the by or waste products of such treatment. To illustrate the smelting operation the ores, the fuels, the fluxes, and every other material entering into the operation are shown. Following through the process, each product of each operation up to the final product of the works is represented; to these are added, where practicable, illustrations of materials of construction, such as fire-clays, sands, &c. The furnaces and tools are shown by specimens, views, and descriptions. The interest and value of these collections does not lie so much in the specimens themselves as in their being thoroughly connected, and in the kind and amount of information that can be given in regard to them.

See the Handbook for more information on

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GEOLOGY
INORGANIC WORLD
MINERALS


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