A Dictionary of Arts, Manufactures and Mines: Containing a Clear Exposition of Their Principles and Practice, المجلد 1

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D. Appleton & Company, 1856

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الصفحة 279 - An ordeal stronger still was then resorted to ^ a train of 200 tons of coals was allowed to rest with all its weight for two hours in the centre of the...
الصفحة 280 - ... 94 of copper, the second much less, and the third only 0'21. It was therefore obvious that the founder, unskilful in the melting of bronze, had gone on progressively refining his alloy by the oxydisement of the tin, till he...
الصفحة 74 - ... cultivation it requires to produce tolerable crops; hence, where the land is very rich, we find in general a slovenly culture ; where the ground is less productive, more labour and skill are applied to compensate for the want of natural fertility. The simplest cultivation is that of the spade, the hoe, and the rake, and on a small scale it is the best ; but spade husbandry cannot be carried to a great extent without employing more hands than can be spared from other occupations. The plough, drawn...
الصفحة 212 - The locomotive boiler is frequently worked up to a pressure of 120 Ibs. on the square inch, and at times, when rising steep gradients, I "have known the steam nearly as high as 200 Ibs. on the inch. In a locomotive boiler subject to such an enormous working pressure, it requires the utmost care and attention on the part of the engineer to satisfy himself that the flat surfaces of the fire-box are capable of resisting that pressure, and that every part of the boiler is so nearly balanced in its powers...
الصفحة 212 - ... to pressure. Locomotive engines are usually worked at 80 to 100 Ibs, on the inch, and, taking one of the usual construction, we shall find, at 100 Ibs. on the inch, that it rushes forward on the rail with a pent-up force within iU interior of nearly 60,000 tons, which is rather increased than diminished at an accelerated speed.
الصفحة 221 - The fusible metal plates, as used in France, are generally covered by a perforated metallic disc, which protects the alloy of which the plate is composed, and allows it to ooze through as soon as the steam has attained the temperature necessary to insure the fusion of the plate. The nature of the alloy is, however, somewhat curious, as the different equivalents have different degrees of fluidity, and the portion which...
الصفحة 39 - The substance to be examined is weighed and put into the flask A, into which water is then poured to the extent of one-third of its capacity. B, is filled with common English sulphuric acid to about half its capacity. Both flasks are then corked (by which they become united by the rectangular tube), and the apparatus is weighed.
الصفحة 421 - ... where it is stirred about occasionally. In the large manufactories of this country, the ignition of the above mixture in pots is laid aside, as too operose and expensive The calcined matter is raked out, and lixiviated with water. The bright yellow solution is then evaporated briskly, and the chromate of potash falls down in the form of a granular salt, which is lifted out from time to time from the bottom with a large ladle, perforated with small holes, and thrown into a draining-box.
الصفحة 361 - America, India, &c., into compact homogeneous blocks, and the cutting of these blocks into cakes or sheets for the stationer, surgeon, shoemaker, &c. 2. The filature of either the Indian rubber bottles, or the artificial sheet caoutchouc, into tapes and threads of any requisite length and fineness, which, being clothed with silk, cotton, linen, or woollen yarns, form the basis of elastic tissues of every kind. 3. The conversion of the refuse cuttings and coarser qualities of caoutchouc into a viscid...
الصفحة 254 - These arc each heated by separate furnaces, so constructed, that a blast of hot air and fire sweeps through them, and gives to the interior the requisite dose of heat in an incredibly short space of time. The first operation in making the biscuits consists in mixing the flour, or rather meal and water; 13 gallons of water are first introduced into a trough, and then a sack of the meal, weighing 280 Ibs. When the whole has been poured in by a channel...

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