THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



AUGUST 1859. 



XV. On the Expansion of Watei' and Saline Solutions at High 

 Temperatures. By li. C. Sorby, F.R.S. (Sfc* 



IN studying the fluid-cavities in various minerals, I found it 

 requisite to ascertain the relation between the temperature 

 and the volume of water and of saline solutions, up to as high a 

 temperature as could be employed with advantage. My chief 

 object was to make out whether there is any such simple rela- 

 tion between the volume and the temperature, that the tem- 

 perature could be readily calculated from the observed volume; 

 which is a most important point in the study of the fluid-cavities 

 in many minerals. 



In his memoir on the dilatation of liquids fj M. Isidore Pierre 

 showed that the expansion of many may be represented very 

 accurately by expressions of the form 



V = l + A^ + B/2 + C/3, 



where V is the volume, t the temperature in degrees Centigrade, 

 and A, B, and C ai'e constants ; the volume at 0° C. being taken 

 for unity. He, howevei", says that the expansion of water cannot 

 be represented by such a formula ; in which remark I think he 

 must especially refer to the expansion below 25° C, for, as I shall 

 endeavour to show, if we only take into consideration tempei'a- 

 tures above that, the expansion may be represented with consider- 

 able accuracy by a very simple expression. Similar formulae are 

 made use of by Kopp in his investigations on the expansion of 

 some liquids J ; but in discussing the expansion of water, he em- 

 ploys four different formula? to enable him to ascertain the 

 volume at any given temperature differing from those actually 



* Communicated by the Author. 



t Annates de Chimie et de Physique, S. 3. vol. xv. p. 32.5. 

 X Poggendorff's Annalen der Physik und Chemie, vol. Ixxii. 1817. pp- 1 

 and 223. 



Phi/. Mofj. S. 4. Vol. 18. No. 118. Avf/. 1859. G 



