Laws of Molecular Force, 



261 



(liquid compression and expansion), third (latent heat) , fourth 

 (critical temperature), and fifth (capillarity) methods are 

 entered in the columns marked 2, 3, 4, and 5. (The modified 

 fourth method was used, namely, M/^SOOT,^.) 



The units are the megamegadyne (10 12 dynes), grm., 

 and cm. 



Table XXIV. 



Substance. 



CS 



PCl 3 



OCl 4 



CHOI, 



C 2 H 5 C1 



C 2 H,Br 



C 5 H 12 ,. 



C 6 H U 



6 H 6 



C 7 H 8 



(OH 3 ) 2 CO 



Methyl butyrate 

 Ethyl butyrate . 





3. 



25-7 



4. 



5. 



26-5 



27-2 



26-9 





397 



41-7 



434 





463 



46-2 



45-6 



330 



38-2 



36-1 



36-8 



223 



28-3 



26-5 







321 



31-5 



29-0 



48-0 





45-3 



47-1 



57-0 





58-5 



59-3 



400 



431 



427 



438 



59-0 



55-8 



56-2 



56-4 





36-0 



31-3 



311 



65-6 



60-4 



55-6 



561 



84-0 



746 



69-5 



71-3 



The satisfactory agreement of these values, calculated for 

 such diverse bodies from such diverse data, must be taken as 

 the verification of the main principles so far unfolded — the 

 chief of which as regards molecular force is that for most 

 compound bodies the internal virial term of the characteristic 

 equation is l/2v below the volume k, and l/(v-\-k) above that 

 volume. 



We see, too, now how important for molecular dynamics is 

 the detailed study of each of the constants k, B, and /3 in the 

 characteristic equations ; but for the present we must refrain 

 from entering on such a study, and must consider the com- 

 parison in the last table as closing for the present the general 

 discussion of the characteristic equation. 



Our immediate object is now to ascertain the law connecting 

 the value of M 2 Z for a body with its chemical composition. 

 On the hypothesis of the inverse fourth power (with the sub- 

 sidiary one of molecular swarms), 



mH = 7rm 2 A(4 log 2L/a- 16/3) ; 

 so that, the bracketed expression being the same for all 

 bodies, m 2 l is proportional to m 2 A, and the law of irrl or M.H 

 will be the law of m 2 A in the expression SAm 2 /-)' 4 for the force 

 between two molecules. In the Phil. Mag. for April 1889 1 

 announced a law for the parameter A, calculated from Schiff's 

 capillary data, which applied fairly well to a large number of 

 organic compounds,but was affected with exceptions subversive 

 of its generality. Applying now the more accurate method of 



