The outlines of physics: an elementary text-book . r, which is made to boil forseveral minutes. After a sufficient length of time has elapsed to driveout the air from the atmosphere above the level of the liquid, andalso to exclude the air contained by the liquid itself, the cork is in-serted into the mouth of the flask and the flame is extinguished. FUSION AND LIQUEFACTION 179 (b) The flask is then inverted. We now have a body of liquid andan atmosphere consisting altogether of its vapor. As the temperaturefalls this vapor is condensed grad-ually, so that the pressure underwhich the liquid ex
The outlines of physics: an elementary text-book . r, which is made to boil forseveral minutes. After a sufficient length of time has elapsed to driveout the air from the atmosphere above the level of the liquid, andalso to exclude the air contained by the liquid itself, the cork is in-serted into the mouth of the flask and the flame is extinguished. FUSION AND LIQUEFACTION 179 (b) The flask is then inverted. We now have a body of liquid andan atmosphere consisting altogether of its vapor. As the temperaturefalls this vapor is condensed grad-ually, so that the pressure underwhich the liquid exists causing a sudden diminution ofpressure, which may be readily doneby pouring cold water over the flask,as in Fig. 149, the liquid will burstinto violent ebullition. The result ofthis boiling is to add new vapor to theinclosed atmosphere, when the boilingwill diminish in Fresh ap-plications of cold from without wiUcause a repetition of the phenomenon,and the experiment may be carried the liquid is quite 163. The Freezing of Water by its Own Evaporation. — By modifying the method of reducing pressure just described,the interesting phenomenon of a liquid boiling at itsfreezing point may beshown. The apparatusnecessary for this ex-periment consists of anair pump (Fig. 150),a bell jar, a flat metallicdish containing a smallamount of water, anda larger dish of porce-lain, also very labor of pumpingmay be greatly reduced ? figTisoT ~ by having the water previously cooled nearly to the freezing point. To suc-ceed in the demonstration it is necessary to place within
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectphysics
