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 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 3 - Mathematical Master of King's College, London, who, with the co-operation of the following gentlemen, will produce a set of books that shall be efficient both for public and self-instruction : — WSB WOOLHOUSE, FRAS, Actuary of the National Loan Fund, Author of several Scientific Works. HENRY LAW, Civil Engineer, Editor and Author of several Professional Works. JAMES HADDON, Arithmetical and Second Mathematical Master, King's College, London.
Seite 5 - ... powder will find the least opposition to its vent in the air. This need not necessarily be the shortest line to the surface; as, for instance, a long line in earth may, from the same charge, afford less resistance than a shorter line in rock. Supposing the matter in which the explosion is to take place to be of uniform consistence in every direction, charges of powder to produce similar proportionate results ought to be as the cubes of the lines of least resistance, and not according to any fanciful...
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 77 - ... 3 oz. per foot will be sufficient. The charges will vary with the tenacity of the rock, but the following may be a general guide : — the line of least resistance being 1, 2, 3, 4, 5, 6 feet, the charge will be 4, 8, 14, 20, 26, 36 ounces. On comparing the charges used at Delhi, where stiff clay was used as tamping, with those in the Jumna where sand was used, the following table is the result...
Seite 76 - I835, at the fortification of Delhi. The jumpers were 6 feet long, and 2j inches in diameter ; the blasts 5 feet deep, and at a distance of 4 feet from each other. The rate of boring varied from 2^ to 5 feet per day's work for two men. A double-headed jumper was used, to render the hole completely circular for the reception of the canister, about...
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 101 - ... limestones, including the magnesian limestones and the oolites, is one of extreme importance in the building arts, comprehending some of the most advantageous materials of construction, and combining great comparative durability with peculiar facilities for working, in which they surpass the sandstones. Of the limestones and the oolites, the principal material is carbonate of lime. The magnesian limestones contain a quantity of carbonate of magnesia, in some cases nearly equal to that of carbonate...
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...

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