THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



JUNE 1877. 



LV. On some Effects of Dissociation on the Physical Proper- 

 ties of Gases. By "W. M. Hicks ; M.A., Fellow of St. Johns 

 College, Cambridge* '. 



THE following pages contain an attempt to discover what 

 effect the dissociation of an elementary or compound gas 

 has upon its physical constants. That dissociation must exist 

 to some extent at all temperatures is exceedingly probable ; 

 and if so, it must necessarily affect the physical properties of 

 the gas ; and especially we might suppose that it would pro- 

 duce variation from Charles's law, and perhaps explain the 

 difficulty hitherto experienced in accounting for the ratio 

 1*408 of the specific heats of a permanent gas. It was under 

 this belief, and also with some hope of throwing a little light 

 on the chemical changes which take place in compound gases, 

 and on mixing different gases, that I undertook the mathema- 

 tical investigation of it. 



I. 



1. Before we can apply mathematical reasoning to the con- 

 sideration of dissociation, it will be necessary to have some 

 hypothesis on the manner in which it takes place. Our hypo- 

 thesis should be one which, while being as simple as possible, 

 is likely to contain the essentials of what really takes place, 

 even though it may not be correct in all its details. Dissocia- 

 tion of a compound gas is that state in which the compound 

 molecules of a gas are split up into their component parts and 

 exist together uncombined. I shall suppose the same also to 

 * Communicated by the Author. 



Phil. Mag. S. 5. Vol. 3. No. 20. June 1877. 2 D 



