Pneumatics: For the Use of Beginners ...John Weale, 1852 - 138 sider |
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30 inches air-pump amount anemometer atmospheric pressure average bodies breeze bulk capillarity carbonic acid cardinal point castor oil changes cistern coincide compression condensed constant cylinder density descends difference of pressures diminished direction effect elastic force equal equator exactly expand feet fluid gauge geometrical progression glass greater half heat height hemisphere human voice inches of mercury increase instrument integrals of wind land breeze latitude length lever limb liquid means measured mercurial column mercury rises metal miles an hour monsoons motion move movement Natural Philosophy neutral point number of vibrations observations oscillations parallel particles pencil period piston portion pressure-plate produce Professor Daniell proportional quantity rain rarefaction ratio resultant rise scale screw siphon sound space spring square foot square inch suppose temperature tion trade-winds tube upper current valve vane velocity vernier vessel vibrations per second warmer Whewell's whole wind blows windward and leeward
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Side 96 - The wind goeth toward the south, and turneth about unto the north; it whirleth about continually, and the wind returneth again according to his circuits.
Side 46 - Change ;' that rain frequently falls when it stands as high as 30 inches, or ' Fair ;' and more particularly in winter, a fine bright day will succeed a stormy night, the mercury ranging as low as 29 inches, or opposite to ' Rain.' It is not so much the absolute height as the actual rising and falling of the mercury, which determines the kind of weather likely to follow.
Side 24 - The motion of the pistons is effected by means of a short crank with a jointed connecting-rod, converting the circular motion given by the lever handle into a vertical one, which is maintained by means of a cross-head, with rollers working between guides.
Side 13 - ... pressures counterbalance each other. In the same manner the fluid atmosphere presses equally in all directions, and the human body immersed in it may be compared to a sponge plunged into deep water ; it is not crushed, because the water fills the cavities of the sponge, and also surrounds it entirely. In like manner our bodies, and even our bones, are filled either with liquids capable of sustaining pressure, or with air of the same density as the external air, so that the outward is counteracted...
Side 48 - It will be necessary, on returning the form when filled, to accompany it with the following data for reduction. A blank is left for this purpose on the back of the form. " The geographical co-ordinates of the place of observation, viz. latitude and longitude. " The altitude of the cistern of the barometer above the level of the sea, exactly ; if not, as near as it can be obtained. " The internal diameter of the tube of the barometer.
Side 25 - B, in which a vacancy is simultaneously made for it by the descent of the piston p; and, in consequence of the difference of capacity of the two cylinders, it becomes reduced to one-fourth of its original bulk, its elasticity, according to the well-known law, being proportionally increased. The air contained in the small cylinder below the piston,/, will, in like manner, be pressed through the valves, v, V, into the atmosphere.
Side 110 - Greenwich during the former year was 18'7, and during the latter 18-3 miles an hour; for the whole integrals of wind for those years, as shown by the length of their type-line, measured along all its windings, was in 1841, no less than 167,322 miles, and in 1842, 159,950 miles ; showing that the whole movement of the air in this country is about four times as great as its resultant or effective movement. The more variable the wind may be at any...
Side 111 - INTEGRATING ANEMOMETER. A SHEET of plain paper, placed in the instrument, under a registering pencil, is moved forward by rotating, hemispherical fans, at the rate of one inch for every ten miles of air that passes ; this same pencil, having a lateral motion given to it by a vane, records the point of the compass from which the wind blows, and a clock-hammer, descending every hour, strikes its mark on the margin of the paper, to express the time. Thus, in a single line, are given the length of the...
Side 30 - ... so as to spout from its extremity with a force depending partly on the degree of condensation, and partly on the elevation of the extremity of the hose above the level of the engine. It is to...
Side 4 - Combustion. greater in summer than in winter, and during night than during day. It is also rather more abundant in elevated situations, as on the summits of high mountains, than in plains ; this is probably owing to an absorption of the gas near the surface of the earth by plants and moist surfaces.