268 



was obtained of inuoh smaller velocity of decomposition than on slow 

 evaporation. Bai.y and Duncan expressed the opinion that this ditference 

 is probably caused by this, that on rapid evaporation there is formed 

 a gas phase rich in the kind of molecules that preponderate in the 

 liquid phase, whereas on slow evaporation there has been a possi- 

 bility for the conversion of this kind of molecules into another, of 

 which the gas phase chiefly consists in ordinary circumstances. 



One kind of molecules, which chiefly occurs in liquid ammonia, 

 would then be the inactive kind, and the other kind of molecules, 

 of which the ordinary ammonia gas chiefly consists, the active one. 

 They further pointed out that the existence of inactive and active 

 kinds of molecules probably accounts for the chemical inactivity of 

 the gas dried by Bakkk. 



So we see that in this paper Bai.y and Duncan already express 

 the supposition at which I had als(j arrived, though 1 did not publish 

 it because my investigation was not yet sufTliciently advanced. Baly- 

 Duncan's results, however, are not very convincing, as Bhiscoe') 

 observed, because they can also be explained in another way. He 

 says: "It is known, that ordinary commercial ammonia, dried over 

 lime, contains about 1 percent of water '), and that rapid, irreversible 

 destination, such as may occur by free discharge of gas from a cylinder 

 of liquid, is a very effective means of sejiaialing the constituents even 

 of a constant boiling mixture'), so that the gas thus obtained may well 

 be considerably drier than that in real equilibrium with the cylinder 

 liquid. Baly has found that the addition of water vapour to ordinary 

 ammonia increases its reactivity, drying certainly decreases its reac- 

 tivity, and so the greater dryness of the "inactive" form would 

 appear to be capable of explaining the whole of the observations, 

 including the "recovery" of the gas in cylinders on standing (by 

 acquisition of the equillibrium content of water vapour) identity of 

 slowly released cylinder gas with laboratory preparations dried by 

 lime, recovery of inactive gas in the experimental tube, when the 

 wire is heated at 200° (release of absorbed water from the wire or 

 walls) and the increase in reactivity of "inactive" ammonia with 

 increase of temperature of the wire". 



These remarks of Briscoe's, which are very true in my opinion, 

 deprive Bai.y's published experiments for the present of all their 



•) Annual Reports of the Progress of Chemistry vol. 19 1922, p. 37. 

 ») Briscoe refers here to White T. 121, 1688 (1922), but this must be a mistake 

 for White has not found this. 



») MuLLiKEN J. Amer. Ghem. Soc. 44, 2389 (1922). 



