BRIDGMAN. — THERMODYNAMIC PROPERTIES OF LIQUIDS. t 



work on water (pages 7 to IS). Then the methods of computa- 

 tion are taken up in detail, describing in succession the method used 

 for each one of the thermodynamic properties (pages 18 to 37). 

 A somewhat detailed analysis of the data for each liquid is next 

 given, including any special features of the experiment for that liquid, 

 the experimental error, and the source and probable accuracy of data 

 by other observers which have been used in the computations (pages 

 37 to 74). Here are included the fundamental data for each 

 liquid, that is, the tables and diagrams of volume against pressure 

 and temperature. The various thermodynamic properties are then 

 discussed, with comments on the peculiarities of the individual 

 liquids, and on the general features common to them all (pages 74 

 to 104). The diagrams for this general discussion are given on 

 folders at the end of the paper, all the diagrams for any one property 

 being collected on one sheet. It is hoped that this arrangement will 

 produce less confusion in the text, and at the same time, permit a 

 more ready general survey of the facts. Finally, there is given on 

 pages 104 to 113, a discussion of the bearing of the results on previous 

 theories, and of the possible effects on our ideas of what the actual 

 mechanism of a liquid may be. 



II. Experimental Method. 



The method is essentially similar to that used in the preceding 

 work on water. As in the earlier work, so here, the liquid under 

 investigation is placed in a cylinder closed by a piston which moves 

 absolutely without leak. The pressure on the liquid may be varied 

 by changing the position of the piston, and the temperature may be 

 varied by altering the temperature of the surrounding bath. The 

 volume is found directly by measuring the position of the piston in 

 the cylinder. The fundamental data to be obtained with the appara- 

 tus are the values of the volume as a function of pressure and tempera- 

 ture at a sufficient number of points to allow the calculation of the 

 volume at any temperature and pressure within the range. 



In actual use the simple procedure suggested above is complicated 

 by the necessity of introducing the instrument for measuring the pres- 

 sure into the same cylinder with the liquid under investigation. 

 The pressure in these experiments was measured with a coil of man- 

 ganin wire, the changes in the resistance of which give the pressure by 

 a previous calibration.* Although this manganin gauge is compact 



4 Bridgman, These Proceedings, 47, 319-438 (1911). 



