262 



APPLICATIONS OF MARIOTTE'S LAW. 



the end which is within the bottle is drawn out into a 

 point. The bottle being inverted, the neck is clamped 

 in the retort-stand and the open end of the bent tube 

 dipped into a glass of water, as shown in the figure. 

 The mouth is next applied to the end of the straight 

 tube, and when the air in the bottle has become suffi- 

 ciently rarefied by suction, water will be thrown into the 

 bottle as a fine jet y and will run out again through the 

 straight tube. Full atmospheric 

 pressure acts on the surface of the 

 water in the glass and at the lower 

 end of the straight tube. At the 

 upper end of both tubes this pressure 

 is diminished by that of the columns 

 of water in them, but since the 

 perpendicular height of the straight 

 tube is greater than that of the 

 other, the pressure at the upper 

 extremity of the bent tube is 

 somewhat greater than that at the 

 upper end of the straight tube. 

 Now, the pressure of the enclosed 

 air, which is in contact with two 

 liquid surfaces under different pres- 

 sure, can evidently not be equal 

 either to one or to the other: it 

 will be intermediate between both 

 pressures, that is, it will be less 

 than that at the upper end of the 



FIG. 182 (| real size). 



bent tube, hence water will he 

 thrown upwards by the latter; and its pressure will 

 be greater' than that at the upper end of the 



