350 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Contents. 



I. Introduction 347 



II. The P-V-T Surface of Liquid Mercury 351 



a. Nature of the Experimental Problem — Difficulties in Measuring 



Comjiressibility at High Pressures 351 



h. Description of the New Method 354 



Formulae 357 



Details of Manipulation 358 



Compressibility of the Steel Piezometers 362 



Discussion of the Method 362 



Hysteresis in the Containing C3'linder 364 



The New Values iij) to 10,000 kgm. — Temperature Coefficient 366 



Comparison with Other Results 367 



c. Data on the Comi)ressibility of Mercury 368 



The Method of adjusting the Data 369 



Comparison with Other Results 376 



d. Discussion of the Results 380 



Compressibility as a Function of Pressure and Tempera- 

 ture 381 



Dilatation as a Function of the Pressure 382 



Variation with Temperature Imperceptible 380 



The Specific Heats • 383 



The Adiabatic Compressibility 384 



The Heat of Compression 384 



Changes of Internal Energy 386 



III. The Change of State, Liquid-Solid 387 



a. The Thermodynamic Data needed — Methods 387 



b. Co-ordinates of the Freezing Curve by Change of Resistance 388 



Method and Details of Manipulation 388 



Data — Method of Adjusting the Values 393 



Incidental Data during Resistance Measurements .... 394 



Electrical Resistance of Liquid Mercury imder Pressure 395 

 Electrical Resistance of Solid Mercury — Change Solid to 



Liquid 395 



Rough Value for Pressure Coefficient of Resistance of Solid 396 

 Comparison with Pre\aous Values for the Resistance of 



the Solid 397 



Resistance of an Amalgam under Pressure 398 



c. The Melting Curve by the Change of Volume Method . . . 399 



The Method 399 



The Apparatus 400 



Order of Procedure ^ 401 



Detailed Discussion of Possible Errors 402 



Leak 402 



Elastic After-Effects 402 



Elastic Deformation — Calculation of Correction . . . 406 



Temperature Corrections 408 



Thermal Dilatation of the Transmitting Liquid .... 410 



