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action angle apparatus application armature arrangement atmospheric atmospheric railway axis balloon battery boiler burning-glass carillon centimetres centre chimney clock colours communication compressed air condenser constructed cylinder daguerreotype decimetre dial diameter direction distance elastic electric electro-magnet employed engine escape eye-piece fire fixed force galvanometer give glass goniometer heat heliostat horizontal hydrometer indicator instrument invention kilogrammes length lens lenses less lever light lightning-conductor liquid locomotive machine magnetic magnifying means mechanism metal metres microscope millimetres mirror motion movable move movement needle needle telegraph negative proof object object-glass obtained ordinary oscillations pantelegraph paper passes pendulum photographic piece pipes piston placed plate pressure principle produced proof pump ratchet-wheel rays regulator reservoir screw side siderostat sound sound-post steam steam-engine stereoscope stringed instruments strings surface telegraph telescope temperature tion transmitting tube valve velocity vertical vessel vibrations violin weight wheel wire
Page 381 - 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 vessel.
Page 660 - Siemens' armature. When the machine was in full action it melted a rod of iron 15 inches in length and a quarter of an inch in diameter, and gave the most brilliant illuminating effects when the discharge took place between carbon points. As nearly as could be estimated, the mechanical force absorbed in producing these results was from eight to ten-horse power. Wilde's machines have been successfully employed by Messrs. Elkington for the precipitation of copper and other metals, and he has lately...
Page 540 - ... sufficient protection for an ordinary building against any thunder-storm in this climate. The copper wire may be built into the wall to prevent theft, but it should be connected to any outside metal, such as lead or zinc on the roof, and to metal rain-water 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 gas-pipes which enter the...
Page 663 - В the helices, or bobbins, are seen both in section and detached ; and at RR the form is shown of one of the insulated copper conductors, to which the contiguous ends of the wires of the helices are attached, and from which the current is drawn off by means of rubbers or brushes formed of flexible bundles of copper wire. These brushes are so applied at the neutral positions of the ring that they begin to touch one of the conductors R, before they have left the preceding one. In this way no actual...
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 xxxv - ... grains. The French measures of weight are derived at once from the measures of capacity, by taking the weight of cubic millimetres, centimetres, decimetres, or metres of water at its maximum density, that is at 4° C. or 39° Fah.
Page 540 - ... no such metallic connections with distant points, it is not necessary to take any pains to facilitate the escape of the electricity into the earth. Still less is it advisable to erect a tall conductor with a sharp point in order to relieve the thunder-clouds of their charge.