Chemical Combination of Gases. 



265 



When things have got into a condition of equilibrium we 



have 



,2 



so 



that 



111 



mn 

 t 2 ' 



VSL 



(30) 



' — — ~> o — j 



«WT. 



(31) 



Or, as the numbers of free atoms and triplets are small 

 compared with the numbers of molecules, we may write this 

 equation as 



= T V*(M-3s) 3 (N-s). 



(32) 



We see from the form of this equation that the combi- 

 nation will be relatively greater at high than at low pres- 

 sures. We may express this equation in words by saying 

 that the ratio of the number of molecules of A 3 B to the 

 number of free molecules of A is equal to the geometric 

 mean of the number of free molecules of A and B multiplied 

 by a constant. 



The most prominent case of combination of this kind is 

 that of the formation of ammonia when the silent electrical 

 discharge is allowed to pass through a mixture of hydrogen 

 and nitrogen. The formation of triplets of hydrogen atoms 

 in this case seems not unlikely, as triplets of oxygen atoms 

 would be formed under the same circumstances. The exist- 

 ence of ozone is detected by its possessing the properties of 

 oxygen in an exaggerated degree, so that it is possible that 

 if the properties of oxygen had not been so marked the 

 existence of ozone might have been overlooked. 



Let us now go on to discuss the second hypothesis. 



Let the notation be the same as before, with the addition 



that — = the time that elapses before an atom of A unites 

 nq 



with a molecule of A and an atom of B simultaneously. 



Then if we suppose that a molecule of A 3 B breaks up into 

 an atom and a molecule of A and a molecule of B, and that 



Phil. Mag. 8. 5. Vol. 18. No. 113. Oct. 1884. T 



