. THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



FEBRUARY 1868. 



XL On certain Thermomolecular Relations of Liquids and their 

 Saturated Vapours. By John James Waterston, Esq. 



[With Four Plates.] 

 To the Editors of the Philosophical Magazine and Journal. 



1 Ar dross Street, Inverness, 

 Gentlemen, August 13, 1867. 



§ 1. IN the Annates de Chimie for May 1859 there is an 

 A account of some experimental researches on the dila- 

 tability of volatile liquids by M. Drion ; and in the Philosophical 

 Magazine for May 1864 I have shown, by a graphical analysis 

 of M. D rion's results, that they indicate, as a general law of 

 liquid expansion, that the inverse of the absolute increment of 

 volume diminishes regularly as the temperature ascends. For 

 example, if a liquid expands * at 0°, aud — 1— at 10° per 1° 

 rise of temperature, it will be found that at 20° the expansion is 

 yi^, at 30° it is ^L- y at 40° it is -^, and so on to 200°, where 

 the rate would be ^, considered purely as a mathematical law. 

 The unit is taken as the volume at a certain fixed temperature, 

 say 0° C. Thus in the above example the expansion of -J— at 

 40°, and ^ per 1° at 50° means the -l^ and ^ oVthe 

 volume it had at 0°, not the -i_ and -i— of the volume at the 

 respective temperatures 40 and 50 . The first is the absolute 

 increment, and the second is the relative increment. M. Drion's 

 observations on muriatic ether and sulphurous acid were so re- 

 gular that it was distinctly brought out by them that the law has 

 Phil. Mag. S. 4. Vol. 35. No. 235. Feb. 1868. G 



