Title: The American Museum journal
Identifier: americanmuseumjo18amer (find matches)
Year: c1900-(1918) (c190s)
Authors: American Museum of Natural History
Subjects: Natural history
Publisher: New York : American Museum of Natural History
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library

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502 THE AMERICAN MUSEUM JOURNAL tojj of which giant trees had grown. For the working of the mine, the land was cleared of trees which later furnished the beams for the shafts. Water was encountered when the work had progressed twenty feet below ground and a diaphragm pump was used. In time, however, the water increased and made conditions so bad that the work had to be continued at another side. The only difference between the process
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British Guiana has already yielded gold-bear- ing material. The gold miners have a simple way of washing earth supposed to contain gold. The dirt is put into a shallow conical-shaped wooden bowl called a batca, which is then slewed about in the water with a circular sidewise mo- tion. A bit of quicksilver in the apex of the cone mingles with the dirt and attaches to itself whatever small particles of gold are present; then, being heavier than the dirt, it sinks back to the bottom again. The earth is gradually washed away by the action of the water and the gold and quicksilver are left in the batea of getting the diamonds from the gravel in the mine and the way in which the work is usually done by pork-knockers, was in the washing of the gravel in "long toms," and the employment of several jiggers instead of one. Of course there was also the advantage that came from good tools for the work. The "long toms" were long troughs placed at the outlets of a dam in the creek. In each trough were inserted three sieves of different-sized mesh. The gravel was dumped into the upper end of the trough and washed down by the pressure of the water coming through from the dam above. The larger stones and gravel were kept back and thrown away. After passing through the "long tfim," the gravel of uniform size fell into a rectangular flat sieve that was suspended by four chains from a scaffolding in such a way that the water in the pool below just covered the bottom of the sieve. A man stood in this water and shook the sieve (lo- cally called a "baby") back and forth. This gave the finishing touches to the washing. Then the gravel was brought to jiggers, and they jigged it in large square boxes which had been filled with water after the seams had been stopped with rags and rubber. This mine undoubtedly has some valuable material in it, but on account of the loose- ness of the gravel which causes cave-ins, and the presence of an excess of water, it has proved a failure as worked. Supplies had to be brought up the river from Georgetown, and as the river has many rapids and falls, nuich hauling and portage was necessary. The only pump that could be had in Georgetown was too small to serve the emergency at the mine, as it could draw up water only twenty feet, and the place has finally been deserted. The buildings by this time have probably disappeared, each board being carried away separately by passing pork-knockers, or by those who came especially to get them. Boards are scarce there, and it could not be hoped that such an unguarded supply would remain long. These diamond gravels, however, are a valuable asset of British Guiana. Even by their primitive methods, the pork-knockers have enriched the colony by hundreds of dol- lars collected as royalties, and have put upon the market many fine gems, besides much hort or chips and small stones, used in Brit- ish manufacturing plants where highly pol- ished surfaces of steel are required. Labor is cheap in British Guiana, from forty-eight to seventy-two cents a day. The men are registered by the government for a period of one hundred and twenty working days and are forced by law to serve the full time. Both diamond and gold-bearing material is here, to be profitably, if scientifically, ex- plored and prospected, for this interior of jungle, savannah, and mountain represents one of the least known places of the world.

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