Records of General Science, Volume 3Robert Dundas Thomson, Thomas Thomson Taylor and Walton., 1836 - Science |
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Popular passages
Page 463 - ... of coke was rather diminished. Hence the increased efficacy of the blast appears to be not greater than was to be expected, from the diminished fuel that had become necessary to smelt a given quantity of iron. On the whole, then, the application of the hot blast has caused the same fuel to reduce three times as much iron as before, and the same blast twice as much as before. The proportion of the flux required to reduce a given weight of the ore, has also been diminished.
Page 464 - ... cwt. a minute, which, when forced in at the ordinary temperature of the air, cannot be conceived otherwise than as a prodigious refrigeratory passing through the hottest part of the furnace, and repressing its temperature. The expedient of previously heating the blast obviously removes this refrigeratory, leaving the air to act in promoting combustion, without robbing the combustion of any portion of the heat it produces.
Page 463 - ... splint coal. During the three successive periods that have been specified, the same blowing apparatus was in use; and not the least remarkable effect of Mr. Neilson's invention, has been the increased efficacy of a given quantity of air in the production of iron. The furnaces at Clyde...
Page 11 - Indeed, throughout the whole of this business, the conduct of Sir Isaac Newton is quite inexplicable. He stopped the press for three months at a time; and, ' to keep all things wholly in his own power (says Flamsteed), he had brought in an undertaker, who was useless to the business, and served only to spoil the work, or worse; and a printer, whom I believe he paid I am sure he never consulted me about the payment of either, though there was sufficient cause, all the articles relating to them having...
Page 464 - ... from the old much more in appearance than in essence and reality. But if two tons of solid material an hour, put in at the top, are not likely to affect the temperature of the hottest part of the furnace, can we say the same of six tons of air an hour, forced in at the bottom near that hottest part ? The air supplied is intended, no doubt, and answers to support the combustion ; but this beneficial effect is, in the case of the cold blast, incidentally counteracted by the cooling power of six...
Page 463 - ... of coal had to be used. This being almost exactly three times as much, we have, from the change of the cold blast to the hot, combined with the use of coal instead of coke, three times as much iron made from any given weight of splint coal.
Page 462 - IronWorks, felt himself encouraged to attempt the substitution of raw coal for the coke before in use. Proceeding on the ascertained advantages of the hot blast, the attempt was entirely successful ; and, since that period, the use of raw coal has extended so far as to be adopted in the majority of the Scotch iron- works.
Page 463 - ... every morning, and another every evening, being consumed in letting off the iron made. But the gaseous material — the hot air — what might be the weight of it? This can easily be ascertained thus: I find, by comparing the quantities of air consumed at Clyde Iron-Works, and at Calder Iron-Works, that one furnace requires of hot air, from 2,500 to 3.000 cubical feet in a minute.
Page 393 - This was done while the female was sitting ; and as the nest had been built when the water level stood low, the sudden influx of this large body of water from the second pond caused a rise of several inches, so as to threaten the speedy immersion and consequent destruction of the eggs. This the birds seem to have been aware of, and immediately took precautions against so imminent a danger ; for when the gardener, upon whose veracity I can safely rely, seeing the sudden rise of the water, went to...
Page 462 - Fahr., one ton of cast-iron required 5 tons 3£ cwt. of coal, converted into coke. The saving amounts to 2 tons 18 cwt. on the making of one ton of cast-iron ; but from that saving comes to be deducted the coals used in heating the air, which were nearly 8 cwt.