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30 inches air-pump anemometer arithmetical progression ascending atmospheric pressure barometer barrel bodies bottom breeze bulk carbonic acid cistern coincide column of mercury column of water compressed condensed air constant containing density depressed descends diminished direction effect elastic force equal equator exactly exhausting cylinder exhausting syringe expand filled floz fluid gases gauge geometrical progression glass greater half heat height hemisphere inches of mercury inclosed increase instrument land breeze latitude length limb liquid lower means measure mercurial column mercury rises metal miles an hour monsoons motion Natural Philosophy neutral point number of vibrations observations one-half open end oscillations particles pencil pipe piston portion of air produce Professor Daniell proportion pump quantity rarefaction rise scale screwed siphon solids sound space specific gravity square inch stop-cock stroke suppose temperature tion trade-winds upwards vacuum valve velocity vernier vessel vibrations per second wind windward and leeward
Сторінка 118 - 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.
Сторінка 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.
Сторінка 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.
Сторінка 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...
Сторінка 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.
Сторінка 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.
Сторінка 132 - 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...
Сторінка 137 - 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...
Сторінка 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...
Сторінка 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.