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

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H.H. Peck, 1863 - 454 Seiten
 

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Seite 219 - This is strikingly shown in an alloy called the " fusible metal," which is composed of 8 parts of bismuth, 5 of lead, and 3 of tin, and melts at 203° F.
Seite 47 - 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 366 - Moses, we discover glass ornaments in tombs which are as old as the days of Moses. According to Pliny and Strabo, the glass works of Sidon and Alexandria were famous in their times, and produced beautiful articles, which were cut, engraved, gilt, and stained of the most brilliant colours, in imitation of precious stones. The Romans employed glass for various purposes ; and have left specimens in Herculaneum of window-glass, which must have been blown by methods analogous to the modern.
Seite 353 - To be a good material for roofing, it should split easily into even slates, and admit of being pierced for nails without fracturing, Moreover, it should not be absorbent of water, either by the surface or edges, which may be tested by weighing, after immersion for a while in water. It should also be free from pyrites, and every thing that can undergo decomposition on exposure.''* FLAGSTONES.
Seite 299 - The amount of arsenic varies from 0 to 10 per cent. One variety from Spain included 10 per cent, of platinum, and another from Hohenstein some gold ; another from Tuscany 2*7 per cent, of mercury. These varieties give off, before the blowpipe, fumes of arsenic and antimony, and after roasting yield a globule of copper.
Seite 314 - ... now in an extremely minute state of division. This black powder ("spongy platinum") is next compressed in steel moulds by the aid of heat and strong pressure ; and when sufficiently compact, is forged under the hammer and then reduced at last to solid masses. This metal fuses readily before the " compound blowpipe ;" and Dr. Hare succeeded in 1837 in melting...
Seite 46 - ... the required angle. To insure accuracy in this respect, hold the instrument and crystal between the eye and the light, and observe that no light passes between the arm and the applied faces of the crystal. The arms may then be secured in position by tightening the screw at o ; the angle will then be measured by the distance on the arc from k to the left or outer edge of the arm cd, this edge being in the line of o, the center of motion.
Seite 425 - ... 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 156 - But when all these various colours, it is called by various names: — it is oriental ruby when red; oriental topaz when yellow; oriental emerald when green; oriental amethyst when violet; adamantine spar when hair-brown ; emery when in granulated masses of bluish- gray ; asteria, or star-stone, when radiated ; corundum when dull and dingy coloured.
Seite 83 - ... generally divides it into two varieties : — First, Coal without Bitumen. Second, Coal with Bitumen. The first variety is known by the general name of Anthracite. It has however various local names. [ANTHRACITE.] It is sometimes very hard, and has a high lustre, and is often iridescent. Besides being used for fuel it is often made into inkstands, small boxes, and other articles of use. This is more especially the case with the Anthracite of America. It is the most common form of coal in the...

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