Laws of Molecular Force. 41 



The equation for the surface-tension of the elements has to 

 be modified from the form in which it was used for compounds, 

 because in the Laws of Molecular Force (Phil. Mag. March 

 1893) it was shown that the virial constant I of compounds 

 falls in the liquid to half of the limiting value in the gas, 

 whereas in the elements H 2 , 2 , and N 2 it retains the same 

 value in both states. Now the equation (9) was designed to 

 give the value of I for compounds in the gaseous state from 

 measurements of their surface-tensions as liquids, therefore 

 in applying equation (2) to the elements we must provisionally 

 divide by 2, and get 



Wl= ^p x 10- 6 « m (M/pJ* , . . . . (19) 



in which M will be taken as the usual atomic weight. The 

 following are the data for the metals and a few other elements 

 given by Quincke (Pogg. Ann. cxxxv. & cxxxviii.), with the 

 values of M 2 / calculated from them by the last equation, also 

 the values of M 2 Z reproduced from Table XXIX. as given 

 by the Kinetic Theory of Solids, and finally the ratio of the 

 two values of M 2 Z. 







Table XXXII. 















Na. 



K. 



Cu. 



Ag. 



Ag. 



Au. 



Au. 







26 



•97 

 237 



37 

 •86 

 45-4 



59 



8-2 



7-2 



43 



10-0 



102 



80 

 100 

 10-2 



100 



17 



102 



131 







17 



MM, 





10-2 



MH 





23-7 



98 



8-2 



10-4 



19-5 



27-1 



35-6 



MH from Ta. 



XXIX.... 



8-6 



16-2 



111 



159 



159 



18-7 



18-7 







2-7 



6-0 



•8 



•7 



1-2 



1-4 



1-9 







Zn. 



Zn. 



Cd. 



Hg. 



Sn. 



Pb. 



Pb. 







88 

 69 

 9-1 

 17-3 

 7-3 



83 

 6-9 

 91 

 163 

 73 



71 



8-4 



129 



24-8 

 9-7 



59 

 13-6 

 14-7 

 24-3 



4-8 



60 



71 



161 



29-6 



10-9 



46 

 110 

 181 

 28-8 

 153 



34 







11-0 



Pm 



M/o„ 





18-1 



M.H 





21-3 



Wl from Ta. 



XXIX.... 



15-3 







2-4 



2-2 



2-5 



5-0 



2-7 



1-9 



1-4 







Sb. 





Bi. 



Fe. 





Pd. 



Pt. 



a 





25 





39 



26 





136 



169 



Pm 





., 65 





9-7 



7-5 





108 



18-9 



M/p 





17-9 





211 



7-2 





9-2 



9-1 



M.H 





. , 14-8 





301 



133 





28-8 



38-1 



M.H from Ta. 



XXIX. .. 



.. 16-4 





161 



169 





20-6 



261 







•9 





1-9 



•8 





1-4 



1-4 



