Transactions of the Geological Society, Volumen4

Geological Society of London, 1817
0 Opiniones
Las opiniones no están verificadas, pero Google revisa que no haya contenido falso y lo quita si lo identifica

Dentro del libro

Comentarios de la gente - Escribir un comentario

No encontramos ningún comentario en los lugares habituales.


Otras ediciones - Ver todas

Términos y frases comunes

Pasajes populares

Página 453 - La Sidérotechnie, ou l'Art de traiter les minerais de fer pour en obtenir de la fonte, du fer, ou de l'acier; ouvrage ordonné par S.
Página 454 - OUTLINES of GEOLOGY; being the Substance of a Course of Lectures delivered in the Theatre of the Royal Institution by WILLIAM THOMAS BRANDE, FRS, Professor of Chemistry in the Royal Institution, &c.
Página 279 - Both varieties are covered with a crust of greenish earth of the same nature with the green particles in the sand. The angular flints appear to have been derived from the partial destruction of the bed of chalk immediately subjacent, of which the upper surface in contact with the sand is considerably decomposed to the depth of about a foot, and its fissures and numerous small...
Página 279 - The oysters of No. 2 are remarkably perfect when first laid open, and seem to have undergone no process of mineralization ; they soon fall to pieces by exposure to air and moisture. The chalk flints contained in it are many of them in the state of small rounded pebbles ; in others the angles are unbroken. Both varieties are covered with a crust of greenish earth of the same nature with the green particles in the sand. The angular flints appear to have been derived from the partial destruction of...
Página 2 - Tees, where it appears as a fine-grained sandstone of a brick-red colour, which effervesces with acids ; its limit on the north-east is a little above the northern bank of the Tees. The strata are numerous, and consist (as far as one can judge from the miner's language) of white, grey, or red sandstone, with occasional interposed strata of a more compact nature, red or blue shale (slate...
Página 11 - ... number, and consist of alternating beds of coal, sandstone, and slateclay; making an aggregate thickness of 1620 feet, which varies however in different parts. The irregularities of the surface do not affect the dip or inclination of the strata; so that when a valley intervenes, they are found in the sides of the opposite hills at the same levels as if the respective strata had once been continuous.
Página 56 - Besides the coal exported to different parts of England, a large quantity is consumed in the two counties, which cannot easily be calculated. About thirty years ago a practice was adopted at the pits, where the coal was of a fragile nature, of erecting screens to separate the small from the sounder coal. This system is now become universal, and immense heaps of coal are thus raised at the mouths of the pits. These soon take fire from the heat of the decomposing pyrites, and continue to burn for several...
Página 448 - The preparation which they undergo is, first, exposure to the sun for some time, and then calcination. The latter process is performed by packing the stones in earthen pots, and covering them with a layer five or six inches thick of dried goat's dung. Fire is then applied, and in twelve hours the pots are sufficiently cool to be removed.
Página 29 - There are several other dykes of the same kind, which, following the same law as the cross veins in the lead mine district, elevate the strata on the side to which they dip. The dykes are an endless source of difficulty and expense to the coal-owner, throwing the seams out of their levels, and filling the mines with water and fire-damp. At the same time they are not without their use; when veins are filled, as is often the case, with stiff clay, numerous springs are dammed up, and brought to the...
Página 54 - Jire-damp, and after-damp or stythe^ are the miners terms for the gasses with which the coal mines are affected, and of these the second, both from its immediate violence and as occasioning the other kinds of damps, is the most to be dreaded. The accidents arising from it have become more common of late years ; but it should not for a moment be Supposed that they arise from any want of skill or attention in the professional surveyors of the mines. The following seem to be the causes in which the...

Información bibliográfica