According to Boussingault, the annual product of Platinum in America does not exceed 81⁄3 cwts. At Nischne-Tagilsk, in 1824, a lump of native platinum weighing fully 10 lbs. was found; and in 1830, another lump, of nearly double size, which weighed 353⁄4 Prussian marcs; fully 18 lbs. avoirdupoise.
PRODUCTION OF PLATINUM IN THE URAL.
| From 1822 to | 1827 | inclusively, | 52 | puds[41] and | 22 | 1⁄2 | pounds. |
| 1828 | 94 | ||||||
| 1829 | 78 | 31 | 1⁄2 | ||||
| 1830 | 105 | 1 | |||||
| 1831 | to 1833 | 348 | 15 | ||||
[41] One pud = 40 Russian pounds, = 69,956 Prussian marcs (see [Silver]); 1 pound = 96 zolotniki.
Analyses of the Platinum Ores of the Urals, and of that from Barbacoas on the Pacific, between the 2nd and 6th degrees of northern latitude.
| From Nischne-Tagilsk. | Goroblagodat. | Barbacoas. | |||
|---|---|---|---|---|---|
| Berzelius. | Osann. | Berzelius. | |||
| Magnetic. | Not Magnetic | ||||
| Platinum | 73·58 | 78·94 | 83·07 | 86·50 | 84·30 |
| Iridium | 2·35 | 4·97 | 1·91 | — | 1·46 |
| Rhodium | 1·15 | 0·86 | 0·59 | 1·15 | 3·46 |
| Palladium | 0·30 | 0·28 | 0·26 | 1·10 | 1·06 |
| Iron | 12·98 | 11·04 | 10·79 | 8·32 | 5·31 |
| Copper | 5·20 | 0·70 | 1·30 | 0·45 | 0·74 |
| Undissolved Osmium and Iridium | 2·30 | 1·96 | 1·80 | 1·40 | — |
| Osmium | — | — | — | — | 1·03 |
| Quartz | — | — | — | — | 0·60 |
| Lime | — | — | — | — | 0·12 |
| 97·86 | 98·75 | 99·72 | 98·92 | 98·08 | |
PLUMBAGO. See [Graphite], for its mineralogical and chemical characters. The mountain at Borrowdale, in which the blacklead is mined, is 2000 feet high, and the entrance to the mine is 1000 feet below its summit. This valuable mineral became so common a subject of robbery about a century ago, as to have enriched, it was said, a great many persons living in the neighbourhood. Even the guard stationed over it by the proprietors was of little avail against men infuriated with the love of plunder; since in those days a body of miners broke into the mine by main force, and held possession of it for a considerable time.
The treasure is now protected by a strong building, consisting of four rooms upon the ground floor; and immediately under one of them is the opening, secured by a trap-door, through which alone workmen can enter the interior of the mountain. In this apartment, called the dressing-room, the miners change their ordinary clothes for their working dress, as they come in, and after their six hours’ post or journey, they again change their dress, under the superintendence of the steward, before they are suffered to go out. In the innermost of the four rooms, two men are seated at a large table, sorting and dressing the plumbago, who are locked in while at work, and watched by the steward from an adjoining room, who is armed with two loaded blunderbusses. Such formidable apparatus of security is deemed requisite to check the pilfering spirit of the Cumberland mountaineers.
The cleansed blacklead is packed up into strong casks, which hold 1 cwt. each. These are all despatched to the warehouse of the proprietors in London, where the blacklead is sold monthly by auction, at a price of from 35s. to 45s. a pound.