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Page 383 - Wells was the first to explain the formation, artificially, of ice in Bengal, where the substance is never formed naturally. Shallow pits are dug, which are partially filled with straw, and on the straw flat pans containing water are exposed to the clear firmament. The water is a powerful radiant, and sends off its heat copiously into space. The heat thus lost cannot be supplied from the earth — this source being cut off by the non-conducting straw. Before sunrise a cake of ice is formed in each...
Page 542 - The copper wire may be built into the wall to prevent theft, but should be connected to any outside metal, such as lead or zinc on the roof, and to metal rainwater pipes. In the case of a powder-mill it might be advisable to make the network closer by carrying one or two additional wires over the roof and down the walls to the wire at the foundation. If there are water or...
Page xxxvi - Ib. raised to a height of one foot in one minute of time. The force competent to produce a velocity of one metre in one second, in a mass of one gramme, is sometimes adopted as a unit of force. Unit of Heat.
Page xxxiv - English yard is equal to 0-91438 metre ; while one mile is equal to 1-60931 kilometres. Unit of Surface. — For the unit of surface, the square inch, foot, and yard adopted in this country and in England are replaced in the metric system by the square millimetre, centimetre, decimetre, and metre.
Page 383 - To produce the ice in abundance, the atmosphere must not only be clear, but it must be comparatively free from aqueous vapour. When the straw in which the pans were laid became wet, it was always changed for dry straw, and the reason Wells assigned for this was, that the straw, by being wetted, was rendered more compact, and efficient as a conductor. This may have been the case, but it is also certain that the vapour rising from the wet...
Page xxxiii - Treasury, a new standard yard, bearing the proportion to a pendulum, vibrating seconds of mean time, in the latitude of London, in a vacuum, and at the level of the sea, as 36 inches to 39
Page 542 - British wire-gauge (0'238 inch diameter), carried round the foundation of the house, up each of the corners and gables, and along the ridges. The copper wire may be built into the wall to prevent theft ; and it should be connected to any outside metal, such as the lead or zinc on the roof, and to metal rainwater pipes, &c. Highgate, N., August 1889. • On this subject see Faraday, 'Experimental Researches,
Page 446 - Taylor it was determined to substitute steam power for manual labour. For this purpose, in the early part of 1788, Taylor introduced William Symington, an engineer at Wanlockhead Lead Mines, who had previously obtained letters patent (June 5,1787, No. 1,610) for "his new invented steam engine on principles