OCR Text |
Show ANOTHER RARE METAL COMING INTO NOTICE The fruitful activity In experimental mctallurglc work durlnir recent years for both scientific and commercial purposus, especially In electro-metallurgy, has made possible the reduction of metals that wero neforo unutilised and almost unknown. The determination of tho properties of these inotals has suggested uses for them, with the result that there Is a growing demand for ores that but a few years ago wore sought only as mineral curiosities. One of tho most remnrkablo of these metals la tantalum. It Ih not attacked by hydrochloric, nitric, or sulphuric acids, nqua regln, or alkaline solutions. It can bo drawn Into fine wire having a tensile strength greater than soft steol. A red-hot red-hot lump of tantalum may bo at onco hammered Into a pinto which, on repeated rohammorlng, becomos ns hard as diamond. dia-mond. A diamond drill running conllnu-ouslv conllnu-ouslv for three days at 5000 revolutions a minute failed to' penetrate such a plate, although It was but 1 millimeter thick, while tho drill was much worn. A lJrltlah patent has been obtained for making writing pens from tantalum, whose hardness, elasticity, and resistance to corrosion would seem to fit it well for such use. , Tantalum Is now employod principally aa a filament In on electric lntymlcscent lamp which was put on the .Imerloan market in 190C. This lamp consumes but two watts per candlcpower, ns against moro than thrco watts per candlcpower for the ordinary carbon lllamont lamp. An ndvnnco chapter from "Mineral Resources Re-sources of the United States, Calendar Year 1900," on tho production of tantalum and other rare metals, by Frank L. Hcff. is now veadv for distribution by tho United Unit-ed States Geological Survey. The principal ores of tantalum are tnn-tallte tnn-tallte nnd colurablto (a combination of Iron, tantalum, and columblum), which occur In pegmatites, or coarso granites. In tho United Stntcs tantalum ore may be found probably In the greatest nuan-tltv nuan-tltv In the Black Hills of aouth Dakota. In" 1906 one mass weighing 600 Punds was discovered A small lot was shipped to Germany from Canyon, Colo., ""rim? the year, and small shipments have also boon made from Mitchell county, N. C. |