326 Scientific Proceedings, Rogal Dublin Society. 



older one; but the pressure-tube, in this case, passes almost to the 

 bottom of the flask, and below the surface of the liquid. It is 

 essential that the end of this tube, b, dipping below the surface of 



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the water in the flask, be contracted, in order to prevent the 

 rapid siphoning over of the liquid in the flask. 



When the liquid in the flask is heated to boiling-point, air 



