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XIII. An Apparatus for Measuring the Compressibility of 

 Liquids. By S. Skinner, M.A. : Demonstrator at the 

 Cavendish Laboratory , Cambridge*. 



THE special features of the apparatus are [a) its very large 

 bulb, (b) an arrangement to facilitate the filling and 

 emptying processes. The volume of the globe is 1300 cubic 

 centimetres, so that a small alteration of pressure, such as 

 half an atmosphere, produces a considerable movement of the 

 index in the capillary tube of which the capacity per cm. 

 is '003 cubic centim. To facilitate the introduction of liquids 

 a second tube, closed by a stop-cock, is sealed in at the lower 



portion of the globe, and this is connected by a rubber- tube 

 with a side reservoir. If a liquid be poured in the reservoir 

 and the stop-cock be opened, the liquid will flow into the 

 globe. The apparatus is supported on a base-board through 

 which the tube carrying the stop-cock passes. A bell-jar 

 stands on the base-board and is in connexion with a condensing 

 air-pump and a mercurial pressure-gauge. 



The behaviour of the apparatus has been tested by using it 

 for a determination of the compressibility of water, with the 

 following results : — 



-p ■• Calculated from Tait's 



-round. Extrapolation Formula. 



At 5°-45C -0000510 -0000502 



9°-4 -0000501 -0000488 



12°-4 -0000485 -0000479 



16°-2 -0000480 -0000468 



* Communicated by the Physical Society : read May 9, 1891. 



