Manual of Mineralogy: Including Observations on Mines, Rocks, Reduction of Ores, and the Applications of the Science to the Arts ... : Designed for the Use of Schools and Colleges

H. H. Peck, 1877 - 456 Seiten

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Seite 51 - I.) ; hence the sum of all the angles, both interior and exterior, is equal to twice as many right angles as there are sides to the polygon. But the sum of the interior angles alone, less four right angles, is equal to the same sum (Prop.
Seite 309 - ... agents, renders it of great value for the construction of chemical and philosophical apparatus. The large stills employed in the concentration of sulphuric acid are now made of platinum ; but such stills are gilt within, since platinum when unprotected is acted upon by the acid, and soon becomes porous. It is also used for crucibles and capsules in chemical analysis ; for galvanic batteries ; as foil, or worked into cups or forceps, for supporting objects before the blowpipe. It alloys readily...
Seite 304 - After the furnace is charged, the fire is made up ; and the main object of the smelter is to bring the substances into fusion : it is therefore, in this respect, different from the calcining process. When the ore is melted, the door of the furnace is taken down, and the liquid mass well rabbled or stirred, so as to allow of the complete separation of the metallic particles from the slags or earthy matters, and to get the charge clear of the bottom of the furnace, which is made of sand, and soon becomes...
Seite 311 - Extraction of Palladium in Brazil. The extraction of palladium, from the auriferous sand of Brazil, consists in fusing it with silver, and, consequently, forming a quaternary alloy of gold, palladium, silver, and copper, which is granulated by projecting it into water. By treating this alloy with nitric acid, the gold is separated from the other metals which are soluble in the acid; the silver is precipitated by a solution of common salt in the state of insoluble chloride, which being separated,...
Seite 93 - ... working dress in an apartment on going in and take it off on coming out. In an inner room two men are seated at a large table assorting and dressing the graphite, who are locked in while At work and watched by the steward from an adjoining room, who is armed with two loaded blunderbusses. This is leemed necessary to check the pilfering spirit of the Cumberland mountaineers. In some years the net produce of the six weeks* annual working of the mine, has amounted to £40,000.
Seite 429 - ... and of various degrees of glassy lustre to a dull stone without the slightest glistening. The common grayish cobble-stones of the fields are usually quartz, and others are dull red and brown ; from these there are gradual transitions to the pellucid quartz crystal that looks like the best of glass. Sandstones and freestones are often wholly quartz, and the seashore sands are mostly of the same material. It is therefore probable that this mineral will be often encountered in mineralogical rambles.
Seite 361 - such was the care of the ancients to provide strong and durable materials for their public edifices that but for the desolating hands of modern barbarians, in peace and in war, most of the temples and other public monuments of Greece and Rome would have remained perfect at the present day, uninjured by the elements during two thousand years.
Seite 103 - ... for pyrotechnic purposes, fulminating powders, and sparingly in medicine. Obs. Occurs in many of the caverns of Kentucky and other Western States, scattered through the earth that form
Seite 361 - ... modern barbarians, in peace and in war, most of the temples and other public monuments of Greece and Rome would have remained perfect at the present day, uninjured by the elements during 2000 years. The contrast in this respect of the works of modern architects, especially in Great Britain, [much...
Seite 411 - Also, 4 inches are 1 hand; 6 feet 1 fathom; -40 rods 1 furlong ; 8 furlongs 1 mile ; 3 miles 1 league.

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