Rudimentary Treatise on the Blasting and Quarrying of Stone for Building and Other Purposes

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J. Weale, 1849 - 106 Seiten
 

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Seite 105 - Church, etc.; and from the results of experiments . . . ; for crystalline character, combined with a close approach to the equivalent proportions of carbonate of lime and carbonate of magnesia; for uniformity of structure...
Seite 103 - ... proportion as the stone employed in magnesian limestone buildings is crystalline, so does it appear to have resisted the decomposing effects of the atmosphere ; a conclusion in accordance with the opinion of Professor...
Seite 76 - ... the mine abandoned. In large irregular masses of rock, the depth of the bore, or the intervals between the blasts, will generally represent the line of least resistance, and the following results were obtained in the rock at Delhi, which is hard quartz. The line of least resistance not exceeding one foot, a charge of 2 oz. is sufficient ; the line not exceeding 4 feet, and the rock not being highly crystalline, 3 oz. per foot will be sufficient. The charges will vary with the tenacity of the...
Seite 90 - Channel : or, if broken there that it rises again in the Isle of Man, and in the counties of Dublin and Wicklow in Ireland. Blocks of granite are found in the beds of some of the rivers in the northwest part of Yorkshire, and in clay pits in Lancashire and Cheshire, at a great distance from any granite mountains. Most of the granitic rocks on Charnwood Forest are of that kind denominated...
Seite 34 - Burgoyne, writing on the subject of rock-blasting in the Corps Papers of the Eoyal Engineers, said: " the distinct machinery for this purpose (firing by a voltaic battery), the expense, and probably some degree of nicety in its arrangements, even after all the improvements that have been made by Colonel Pasley, would render it inapplicable to ordinary purposes; although for firing very large quantities of powder, under very peculiar circumstances, it has been considered very useful.... simultaneous...
Seite 104 - Cathedral, London, Finished about 1700. Built of Portland oolite from the Grove quarries on the east cliff. The building generally in good condition, especially the north and east fronts. The carvings of flowers, fruits, and other ornaments, are throughout nearly as perfect as when first executed, although much blackened. On the south and west fronts larger portions of the stone may be observed of their natural colour than on the north and east fronts, occasioned by a very slight decomposition of...
Seite 77 - About 13 cubic feet weigh a ton ; the limestone is of alight blue or grey colour, in general free from metallic veins, but with some indications of manganese and ironstone, round pieces of the latter being found in clay beds, intermixed with the rock, and a vein of ironstone four inches thick at the surface of the rock, and dipping towards the south, has been opened. The author then proceeds to describe the general method of making cement in that neighbourhood, and the method which he has employed...
Seite 104 - ... east fronts. The carvings of flowers, fruit, and other ornaments are throughout nearly as perfect as when first executed, although much blackened ; on the south and west fronts, larger portions of the stone may be observed of their natural colour than on the north and east fronts, occasioned by a very slight decomposition of the surface. The stone in the drum of the dome, and in the cupola above it, appears not to have been so well selected as the rest : nevertheless scarcely any appreciable...
Seite 89 - ... glittering substance, principally consists of clay and flint, with a little magnesia and oxide of iron. Instead of the mica, another substance called hornblende, is found in some granites ; hornblende is a dark crystalline substance, composed of flint, alumina, and magnesia, besides a large poportion of the black oxide of iron. Granites in which hornblende exists are sometimes called Syenite, having first been found in the island of Syene in Egypt.

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