18 Mr. W. Sutherland on the Fundamental 



Table IV. 



Values adopted in the rest of this Paper for the Heat of 



Vaporization in kilocalories of a gramme-equivalent. 

 Li, Na, K, Kb, and Cs, 139. Cu and Ag, 59'2. 



£Be, pig, ^Oa, |Sr, and £Ba, 18'9. £Zn and ^Cd, 14*8. £Hg, 62. 



*AL 



14-4. 



|Pb, 16-1. 



i 



15 



As, JSb, 



and ^Bi 



, 11-2. 







Li. 







Na. 







K. 





01. 



Br. 



I. 



CI. 



Br. 



I. 



01. 



Br. 



I. 



18-7 



19-8 

 A g- 



18-7 



23-7 



244 



Cu(ous) 



23-9 



23-9 



24-9 



24-3 



01. 



Br. 



I. 



01. 



Br. 



I. 









192 



19-4 



22-7 



9-7 



11-5 

 JCa. 



134 





iSr. 





01. 



Br. 



I. 



01. 



Br. 



I. 



01. 



Br. 



I. 



12-1 



13-1 



iBa, 



13-1 



124 



13-0 

 iZn. 



13-2 



144 



12-8 



iCd. 



... 



01. 



Br. 



I. 



01. 



Br. 



I. 



01. 



Br. 



I. 



16-6 



161 

 iHg(ic) 



. .. 



7-0 



9-5 

 1A1. 



10'8 



11-0 



123 



iPb. 



10-3 



01. 



Br. 



I. 



01. 



Br. 



I. 



01. 



Br. 



I. 



8-1 



7-9 

 £As. 



81 



3-2 



3-6 

 JSb. 



4-2 



11-3 



11-7 



*Bi. 



10-4 



01. 



Br. 



I. 



01. 



Br. 



I. 



01. 



Br. 



I. 



2-2 



3-0 



4-5 



3-2 



• •• 



... 



5-0 



... 



... 



With these values and Thomsen's thermochemical data, we 

 can now tabulate the heats of formation of the metallic haloid 

 compounds when the reagents and products are both gaseous, 

 for if q is the heat of formation of solid RS from solid metal 

 R and solid halogen S, the latent heats of vaporization being 

 L(RS), L(R), and L(S), then H(RS), the heat of formation 

 of gaseous RS from gaseous R and gaseous S, is 



H(RS) = ? + L(R) +L(S)-L(RS). 



Part I. 

 Inorganic Compounds. 



The haloid compounds of the metals have been chosen as a 

 group in which thermochemical law might be expected to be 

 most easily discernible. The following table of data for their 

 heats of formation has been derived from Thomsen's data in 

 the Thermochemisvhe Untersuchungen, Band iii., where they 



