Transactions of the Society Instituted at London for the Encouragement of Arts, Manufactures, and Commerce, Volúmenes 43-44

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Página 160 - The above figure is a representation of the engine; A is the pipe by which the supply of water is brought from a head, 170 feet above the engine ; B is a vessel containing air, the continual elastic pressure of which prevents the blow that would otherwise be occasioned by the descent of the water; c is a throttle valve...
Página 42 - In some instances it is well to run small wood pegs through the portions of glue, so as to keep them exactly in their proper positions. If the mould be of considerable size, it is better to let it be bound with moderate tightness upon a board to prevent it bending whilst in use ; having done as above described, the plaster of Paris, as in common casting, is to be poured into the mould and left to set. In many instances wax may...
Página 42 - The description thus given is with reference lo moulding those bodies which cannot be so done by any other than an elastic mould ; but glue moulds will be found greatly to facilitate casting in many departments, as a mould may be frequently taken by this method in two or three pieces, which would on any other principle require many.
Página xxxviii - To the person who shall invent and produce to the Society a method, superior to any hitherto known or in use...
Página 302 - An Appeal to the British Nation, on the Humanity and Policy of forming a National Institution for the Preservation of Lives and Property from Shipwreck.
Página 34 - The pot is then turned and fixed in a proper position in the furnace, without being allowed to cool, and is then charged with cold iron, so that the metal, when melted, shall have its surface a little below the mouth of the pot. The iron is melted in about an hour and a half, and no flux or addition of any kind is made use of. A pot will last for fourteen or even eighteen successive meltings, provided it is not allowed to cool in the intervals ; but if it cools, it probably cracks.
Página 113 - II.) where bb is the copper dish, surrounded by a ring of the same, by which the plate is firmly screwed down upon the rim of the main hole. In the middle of...
Página 161 - The rod of the piston w is attached at its top to one end of the beam ; at the other end of the beam is a rod, terminating below in the crank m: the oscillating motion of this crank is transferred, by means of the connecting bar /, to the axis k, on which is placed the curved tooth or cam n...
Página 107 - In making the sword-blades there are several methods used ; some make a pile of alternate layers of soft and hardened steel, with powdered cast-iron, mixed with borax, sprinkled between each layer. These are drawn out to one-third more than the length of the intended blade, doubled up, heated, twisted, and reforged several times ; the twist is brought up in the same way as that in the gunbarrels.
Página xvi - To the person who shall discover to the Society the cheapest and most effectual method of raising water in quantities sufficient to be beneficially employed for the purpose of irrigating land, superior to and cheaper than any other method now in use ; — the Gold Medal, or Fifty Guineas. A model, on a scale of one inch to a foot, with...

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