. The principles of physics. erymolecule in the gaseous ocean is drawn towards the earthscenter by gravitation and the atmosphere is thus bound to theearth by this force, just as is the liquid ocean. Evidently thepressure in the atmosphere due to its weight increases withthe depth; or, since in our position we are more accustomedto speak of hifffit in the atmosphere, decreases with the pressure does not diminish regularly with the hight asin an ocean of incompressible fluid. Air is very compressibleand therefore varies in density. The lower strata of airsustaining the weight of air a
. The principles of physics. erymolecule in the gaseous ocean is drawn towards the earthscenter by gravitation and the atmosphere is thus bound to theearth by this force, just as is the liquid ocean. Evidently thepressure in the atmosphere due to its weight increases withthe depth; or, since in our position we are more accustomedto speak of hifffit in the atmosphere, decreases with the pressure does not diminish regularly with the hight asin an ocean of incompressible fluid. Air is very compressibleand therefore varies in density. The lower strata of airsustaining the weight of air above are relatively much com-pressed, very dense, and elastic. The density and elasticityof the air diminish more rapidly than the hight above sea-level increases. Owing to this fact the greater part of the 156 MOLAR DYNAMICS. mass of the atmosphere is within three and a half miles ofthe sea-level (see Fig. 132). Above this hight the air ismuch rarefied and vanishes, as it were, very gradually intoempty space. ExperimentA Fig. 122. Fill two glass jars (Fig. 122) with water, A having aglass bottom, B a bottom provided by tyinga piece of sheet-rubber tightly over the both in a larger vessel of water, water in A does not feel the downwardpressure of the air directly above it, thepressure being sustained by the rigid glassbottom. But it indirectly feels the pressureof the air on the surface of the water in theopen vessel, and it is this pressure that sustainsthe water in the jar. But the rubber bottomof the jar B yields somewhat to the down-ward pressure of the air, and is forced a glass tube, D, with water, keeping the lower Experiment in a vessel of water, and the upper endtightly closed with a finger. Why does notthe water in the tube fall ? Remove yourfinger from the closed end. Why does thewater fall ? Experiment 3. — Fill (or partly fill) atumbler with water, cover the top closelywith a card or writing-paper, hold thepaper in glace wi
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysics, bookyear1895
