Scientific American Supplement, No. 458, October 11, 1884 by Various
page 35 of 144 (24%)
page 35 of 144 (24%)
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coined in Russia, but it is no longer applied to that use. We have
obtained some very good crude platinum ore from South America and have refined it successfully, but the supply from that source is, as yet, very small. I am not aware that it has been found anywhere else than in Colombia, on that continent, but the explorations thus far made into the mineral resources of South America have been very meager, and it is by no means improbable that platinum may yet be discovered there in quantities rivaling the supply of Russia. "A popular error respecting platinum is that its intrinsic value is the same as that of gold. At one time it did approximate to gold in value, but never quite reached it, and is now worth only $8 to $12 an ounce, according to the work expended upon it in getting it into required forms and the amount of alloy it contains. The alloy used for it is iridium, which hardens it, and the more iridium it contains the more difficult it is to work, and consequently the more expensive. When pure, platinum is as soft as silver, but by the addition of iridium it becomes the hardest of metals. The great difficulty in manipulating platinum is its excessive resistance to heat. A temperature that will make steel run like water and melt down fireclay has absolutely no effect upon it. You may put a piece of platinum wire no thicker than human hair into a blast furnace where ingots of steel are melting down all around it, and the bit of wire will come out as absolutely unchanged as if it had been in an ice box all the time. "No means has been discovered for accurately determining the melting temperature of platinum, but it must be enormous. And yet, if you put a bit of lead into the crucible with the platinum, both metals will melt down together at the low temperature that fuses the lead, and if you try to melt lead in a platinum crucible, you will find that as soon as the |
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