Manual of Mineralogy: Including Observations on Mines, Rock, Reduction of Ores, and the Applications of the Science to the Arts, with 260 Illustrations, Designed for the Use of Schools and Colleges

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H.H. Peck, 1876 - 454 Seiten
 

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Seite 309 - 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 when heated with iron, lead, and several of the metals, and is also attacked by caustic potash and phosphoric acid, in contact with carbon ; and consequently there should be caution when heating it not to expose it to these agents. It is employed for coating copper and brass ; also for painting porcelain and...
Seite 160 - Plantes of Paris, for which he gave £3000 sterling. The largest oriental ruby known was brought from China to Prince .Gargarin, governor of Siberia ; it afterwards came into the possession of Prince Menzikoff, and constitutes now a jewel in the imperial crown of Russia.
Seite 84 - Fine drills are made of small splinters of bort, which are used for drilling other gems, and also for piercing holes in artificial teeth and vitreous substances generally. The diamond is also used for lenses for microscopes. When ground plano-convex, they have but slight chromatic aberration, and consequently a larger field, and but little los* of light, compared with similar lenses of other materials.
Seite 357 - 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 49 - ... be produced in the same direction ; then the sum of the exterior angles A, B, C, D, E, will be equal to four right angles. For each interior angle, together with its adjacent exterior angle, is equal to two right angles (Prop.
Seite 35 - Note. — What is meant by replacement, bevelment, and truncation? * To avoid circumlocutions, the following technical terms are employed in describing the modifications of crystals. Replacement. An edge or angle is replaced, when cut off by one or more secondary planes, (tigs.
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 351 - When i> contains hornblende in place of mica, it is called syenite , hornblende resembles mica in these rocks but the laminae separate much less easily and are brittle. Granite is said to be micaceous, feldspathic, or quartzose, according as the mica, feldspar, or quartz, predominates. It is called porphyritic granite, when the feldspar is in large crystals, and appears over a worn surface like thickly scattered white blotches, often rectangular in shape. Graphic granite has an appearance of small...
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 352 - Lowell, and an ex* cellent variety is obtained at Pelham, a short distance north in New Hampshire. Masses 60 feet in length are obtained at several of the quarries. They are worked into columns for buildings, many fine examples of which are common in Boston, New York, and other cities. Good granite is also quarried in Waterford, Greenwich, and elsewhere, in Connecticut. The granite is detached in blocks by drilling a series of holes, one every few inches, to a depth of three inches, and then driving...

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