. The Ontario high school physics. y full of water (Fig. 170).A small glass tube B, drawn to a point,also passes through the cork of thebottle and reaches nearly to the bottomof the bottle. Now hold over the porous cup abell-jar full of dry hydrogen, or passilluminating gas by the tube G intothe bell-jar. Very soon a jet of waterwill spurt from the tube B, sometimeswith considerable force. After this ac-tion has ceased remove the bell-jar, and bubbles will be seenentering the water through the lower end of the tube B. At first the space within the porous cup and in the bottleabove the water is
. The Ontario high school physics. y full of water (Fig. 170).A small glass tube B, drawn to a point,also passes through the cork of thebottle and reaches nearly to the bottomof the bottle. Now hold over the porous cup abell-jar full of dry hydrogen, or passilluminating gas by the tube G intothe bell-jar. Very soon a jet of waterwill spurt from the tube B, sometimeswith considerable force. After this ac-tion has ceased remove the bell-jar, and bubbles will be seenentering the water through the lower end of the tube B. At first the space within the porous cup and in the bottleabove the water is filled with air, and when the hydrogen isplaced about the porous cup its molecules pass in through thewalls of the cup much faster than the air molecules come this way the pressure within the cup is increased, and this,when transmitted to the surface of the water, forces it out ina jet. When the jar is removed the hydrogen rapidly escapesthrough the porous walls and the air rushing in is seen tobubble up through the Fig. 170.—Experiment showingrapid passage of hydrogenthrough a porous wall. 138 THE MOLECULAR THEORY OF MATTER 156. Molecular Motions in Liquids. In liquids the motionsof the molecules are not so unrestrained as in a gas, but onecan hardly doubt that the motions exist, however. Indeed,some direct evidence of these motions has been , an English botanist, in 1827, with the assistance of amicroscope, observed that minute particles like spores ofplants when introduced into a fluid were always in a state ofagitation, dancing to and fro in all directions with considerablespeeds. The smaller the particle the greater was its velocity,and the motions were apparently due to these particles beingstruck by molecules of the liquid. More recently a methodhas been devised for demonstrating the presence of particleswhich are too small to be seen with a microscope, and by meansof it the particles obtained on making an emulsion of gambogein water (whic
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