The outlines of physics: an elementary text-book . ition shown in the figure,with the pump inserted vertically inthe upper cone. By crowding the noz-zle of the pump firmly down into thecone, a small volume of air is trappedabove the upper face of the pile. This air will be compressed bythe action of the pump. (c) Work the pump rapidly, but with care, observing the galva-nometer. It will be found that the latter responds to evei-y stroke, andthat the deflection is in the direction which corre-sponds to the heating of the upper face of the pile. 172. The Fire Sjrringe. — Another formof apparatus
The outlines of physics: an elementary text-book . ition shown in the figure,with the pump inserted vertically inthe upper cone. By crowding the noz-zle of the pump firmly down into thecone, a small volume of air is trappedabove the upper face of the pile. This air will be compressed bythe action of the pump. (c) Work the pump rapidly, but with care, observing the galva-nometer. It will be found that the latter responds to evei-y stroke, andthat the deflection is in the direction which corre-sponds to the heating of the upper face of the pile. 172. The Fire Sjrringe. — Another formof apparatus for the demonstration of theheat produced in compressing a gas isthe fire syringe. This is simply a smallcompressing pump without valves (). The experiment consists in plac-ing a shred of gun cotton (not more thanwill go loosely into the bottom of anordinary thimble) in the bottom of thecylinder of the syringe. The piston isthen inserted, and is driven suddenlydownwards. If the stroke be sharp andvigorous, the heat generated will ignite. Fig. 159. RELATIONS BETWEEN HEAT AND WORK 191 the gun cotton explosively, with a puff of smoke. Theresult does not follow a slow stroke, because of the ra-pidity with which the heat is imparted to the walls of thecylinder. 173. Experiment 48. — Cooling by the Expansion of a Gas. Apparatus : (1) The compression pump described in Exp. 46 (Art. 169).
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectphysics
