338 



Mr. Gervaise Le Bas on 



The following is a suitable method for the demonstration 

 of the approximate validity of the valency law at the boiling 

 and the critical points ; arid it is especially significant owing 

 to the fact that no preliminary assumptions are made. It is 

 also adapted to showing that the following relations are not 

 admissible, viz. C = 2H (Kopp), C = H (Schroder). 



C 

 Table XII. — Investigation of the ratio rj at the Boiling and 



Critical Points. 

 At the B.P. 



No. 



1. 



2. 



3. 

 4. 

 5. 



Hydrocarbon. 



W. 



26 

 32 

 38 

 44 

 50 



V. 



Eatios 



(obs.). 



Theoretical. 



LeBas, 

 C=4H 



a 1 Ko PP> 

 A ' !c = 2H 



A. 



Schroder, 

 C=H 



A. 



n Butane, C 4 H 10 

 n Pentane, C 5 H 12 

 n Hexane, C 6 H U 

 n Heptane,0-H 1G 

 n Octane, C 8 H 18 



96-0 

 117-80 

 139 93 

 162-56 

 186-26 



1-0000 

 1-2271 

 1-4576 

 1-6933 

 1-9402 



1-0000 



1-230 



1-461 



1-693 



1-923 



+0-003 

 +0-003 

 +0-U00 

 -0-017 



1000 

 1-222 

 1-444 

 1-666 



1-888 



-6-005 

 -0-013 

 -0-027 

 -0-052 



1-000 

 1-214 

 1-428 

 1-642 



1-857 



-6-013 

 -0 030 

 -0051 

 -0-083 



-0-045 



Mean e 



rrors 



—0002 





-00191 





















At the Critical Point. 



No. 



Hydrocarbon. 



W. 



V. 



Eatios 

 (obs.). 



Theoretical. 



A. 



1. 

 2. 

 3. 

 4. 



5. 



n Butane, C 4 H 10 

 n Pentane, C-H 12 

 n Hexane, C H 14 

 n Heptane, C T H 1C 

 n Octane, C 8 H 18 



26 

 32 

 38 

 44 

 50 



251-0 

 309-2 

 366-1 

 425-7 



488-9 



1-0000 



1-2310 



1-458 



1-698 



1-948 



1-000 

 1-230 

 1-461 

 1-693 

 1-923 



-'•001 

 +0003 

 -0-005 

 -0025 



Mfian 





-0-007 













The ratios advocated by Kopp and Schroder respectively 

 are seen to be inadmissible, while, on the other hand, the 4 : 1 

 rule very approximately reproduces the observed results. 

 Kopp's constants were obtained by means of comparisons 

 between the volumes of members of very different classes of 

 compounds, and, as will afterwards be shown, are not to be 

 relied on. 



