340 Albert P. Mathews 



Before discussing these results a word may be said about 

 the reliability of the critical data. Those of argon and xenon 

 are perhaps the most certain; krypton, neon and helium 

 follow in the order named, helium being least certain. Onnes 1 

 gives 5.5 absolute as the critical temperature of helium, 

 but as this makes helium quite aberrant in several particulars, 2 

 I have also computed the valence assuming the critical tem- 

 perature to be 8 as suggested by Dewar. 3 The critical data 

 of neon are somewhat uncertain, due in part to the very low 

 critical temperature and in part to the great difficulty in 

 separating the gas completely from helium. A little im- 

 purity of the latter gas would have the effect of making P c 

 too high. 



It is clear, from the table that all of these gases possess 

 valence. They are not zero valent as they are supposed by 

 many to be. Furthermore, the average number of valences 

 per molecule is in no case an exact integer, although in argon 

 and xenon it is not far from a whole number. Since these 

 gases have their critical data most accurately determined 

 I at first supposed, as I published in my preliminary paper, 

 that argon was univalent, but slightly associated into di- 

 atomic molecules, thus bringing the average number of 

 valences per molecule a little high; and that xenon was di- 

 valent. I attributed the deviation of the other gases from 

 uni valency, to the inaccuracy of the data. A careful ex- 

 amination of all the facts, however, has led me to abandon 

 this explanation for what seems to me to be a better one, 

 since it explains all the facts. 



In the first place, I have not been willing to abandon the 

 idea that valences are indivisible. If we assume, as Lodge 4 

 suggests, that some of the lines of force from each valence 

 attach themselves to several atoms, or even wander outside 



1 Onnes: Proc. Amsterdam Acad. Sci., 13, noo (1-911). 



2 Rankin: "On a Relation between Viscosity and Atomic Weight of 

 Inert Gases," Phil. Mag., [6] 21, 45 (1911). 



3 Dewar: Article "Liquid Gases," Encyclopaedia Britannica, 16, 749, 

 nthed. 



4 Lodge: Nature, 70, 176 (1904). 



