An Elementary Introduction to the Knowledge of Mineralogy: Comprising Some Account of the Characters and Elements of Minerals; Explanations of Terms in Common Use; Descriptions of Minerals, with Accounts of the Places and Circumstances in which They are Found; and Espcially the Localities of British Minerals

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W. Phillips, 1823 - 406 páginas
 

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Página lxviii - 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.
Página lxxxii - Cleavage. This term is most commonly used in relation to the fracture of those minerals which, having natural joints, possess a regular structure, and may be cleaved into more or less geometrical fragments; as, into varieties of the parallelepiped, the rhomboid, &c. Coherent. In minerals that are brittle, the particles are strongly coherent; in such as are friable, they are slightly coherent. Columnar distinct concretions ; a term used to express the great and small columns in which certain...
Página 363 - Albania ; but no where so largely as in the island of Trinidad, where it. forms a lake three miles in circumference, and of a thickness unknown A gentle heat renders it ductile, and, when mixed with grease or common pitch, it is used for paying the bottoms of ships, and is supposed to protect them from the teredo of the West Indian seas. The ancients employed bitumen in the construction of their buildings. The bricks of which the walls of Babylou were built BITUMEN— BLACKBIRD.
Página 358 - It is shaped like an egg, with an indented hollow near the smaller end. It is said to be of the finest water.
Página 147 - ... in Pentelican marble have been decomposed, and sometimes exhibit a surface as earthy and as rude as common limestone. This is principally owing to veins of extraneous substances which intersect the Pentelican quarries, and which appear more or less in all the works executed in this kind of marble.
Página xxxvii - THE specific gravity of a body is its weight compared with that of another body of the same magnitude.
Página 160 - England, are entirely composed of it. The lime obtained from it is greatly esteemed for cements, being less subject to decay, owing to its absorbing less carbonic acid from the atmosphere than the lime of common limestone.
Página vi - Haiiy has enabled him, in several instances, to declare the probable form of the primary, from the directions of the crevices, or appearances of natural joints which may be observed in the fragment; and, in many, these have afterwards proved to be correct. By the other mode, the primary form is determined by analogy, that is, by a comparison of the forms of the crystals of a mineral with those of other knoion substances ; but this may in some cases prove a source of error.
Página lxxxiii - An efflorescence is the consequence of chemical action ; it is usually applied to such minerals as are found in extremely minute fibres on old walls, &c. &c. Elastic. A mineral which after being bent, springs back to its original form, is elastic.
Página 292 - Copper is of a lead or irongray color. It occurs crystallized in regular six-sided prisms, mostly modified on the terminal edges, and in acute, double, six-sided pyramids, with triangular planes. It also occurs massive. The cross-fracture of the crystallized is often conchoidal, with a vitreous lustre : the massive varies greatly in respect of hardness and color. It is sometimes sectile and soft. The fracture is even, or flat couchoidal.

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