266 



Prof. T. Carnelley on the Periodic Law. 







Table VII.- 



-Illustrating 



Relat 



ion 7. 









I. 



Diff. of 

 atomic 



weights 

 of ele- 

 ments 

 in I. 



Methides. 



| 



Ethides. 



1 



Propides. 



BUTIDES. 



Phenijdes. 



B.P. 



Sp. gr. 



B.P. 



Sp. gr. 



B.P. 



Sp. gr. 



B.P. 



Sp. gr. 



B.P. 



Sp. gr. 



Br-01... 

 I-Br ... 

 I-Cl ... 



44'5 

 47-0 

 91*5 



28 

 40 

 68 



'•*6()6 



27 

 33 

 60 



•543 

 •476 



25 



31 



56 



•492 

 •359 



22 



30 



52 



•412 



•281 



23 

 34 



57 



•373 

 •138 



Pb-Sn... 

 Sn-Si ... 

 Pb-Si ... 



89 



90 



179 



82(?) 

 48 

 130 



•720 



19 

 29 



48 



•398 

 •421 



•784 



12 



•417 











Hg-Zn.. 



135 



48 



1-683 



41 



1-262 



32 



1-026 



18 









Relation 8. (a) The differences between the boiling-points 

 {and also beticeen the specific gravities) of the methides, ethides, 

 propides, Sfc. of the elements of the seventh or halogen group and 

 those of the elements of groups iii. to vii. respectively increase 

 algebraically from the methides to the ethides, and thence to the 

 propides fyc. (See Table VIII.) 



(b) With members of the second group (Zn, Hg, &c.) these 

 differences as regards the specific gravities diminish algebraically 

 from methides to butides. (See Table VIII.) Whilst as regards 

 the boiling-points of the second group, the first part of the 

 rule (a) seems to hold good, except in so far as a tendency to 

 a reversal of the rule appears as we approach the butides and 

 higher alkyl compounds ; and this reversal becomes the more 

 pronounced the greater the difference in the atomic weights of 

 the metal and the halogen. Data are entirely wanting for 

 the first group. 



Relation 9. The differences referred to in Relation 8, for 

 both boiling-points and specific gravities, increase algebraically 

 as the algebraic difference between the atomic weights of the 

 positive elements increases, (See Table VIII.) 



