784 Dr. R. D. Kleeman on the Nature of the 



chloride, benzene, fluor-benzene,bromo-benzene,iodo-l>enzene. 

 This gave, putting H = l, the values H= 1, C = 5*30, = 5*94, 

 F = 5'76, Cl = 8-40, Br=1065, Sn = 14'68, 1=15-49, which 

 were then used for calculating the value o£ Xc a for the rest 

 of the compounds. The above equations were applied to a 

 large number of liquids, and a fair agreement with the facts 

 obtained. 



The constant c a on account of its independence of chemical 

 combination, temperature, &c, one would expect to be of 

 fundamental importance. An endeavour was therefore made 

 to connect it with some known fundamental quantity of the 

 atom, as its atomic weight. The result obtained was that it 

 is proportional to the square root of the atomic weight of the 

 atom or to its chemical valency. This shows that the valency 

 of an atom is proportional to the square root of its atomic 

 weight, a result already obtained by Traube *. We may 

 therefore write £ \/m 1 or %v for Xc a , where X\/m.\ denotes 

 the sum of the square roots of the atoms of a molecule, and 

 2v denotes the sum ot the maximum valencies of the atoms. 

 The molecular weight of a molecule, it should be noted, is 

 denoted by in. This statement will now be tested in different 



According to equation (2) the expression is propor- 

 tional to %c a , and should therefore be proportional to 2 V^'i 



and z,v. The ratio ~^ — 1=^ is given for a number of liquids 

 pX sjm, x & _ x y 2m _ 



in the third column of Table I., and the ratio _^ is given 



pZv s 



in the fourth column. Both of these ratios, it will be seen, 

 are fairly constant. It should be mentioned that the quantities 

 p and X relate to § Tc, and are taken from the first paper 

 by the writer mentioned, being obtained from the surface- 

 tension and density determinations of Ramsay and Shields. 

 When any of the data used in this paper are not given they can 

 be obtained from the above paper. The values of X y/m 1 a.nd 

 Xv are given for a large number of liquids in Table II. The 

 values of Xv were obtained by putting H = l, = 4, N = 3, 

 = 4, F = 4, Cl = 7, Br = 10, Sn = 10, 1 = 13, the usually 

 accepted maximum valencies of the atoms (Traube, loc. cit.). 



The sixth and seventh columns ot Table I. contain the 

 values of 



Wm E 12 m 



and 



p%^/m x p%v 



respectively, corresponding to § T c . Both ratios are 

 * Phy.°. Zeit. p. 6(37, Oct. 1909. 



