332 BULLETIN OF THE UNIVERSITY OF WISCONSIN. 



In table 12 giving the results for ISFaCl it appears that the 

 molecular weight decreases steadily with the increase of con- 

 centration 1 , becoming in the strong solutions less than half the 

 theoretical molecular weight. The facts then indicate that the 

 dissociation of common salt would increase with the con- 

 centration and that in solutions above about 20 per cent, the 

 molecule would break up into more than two parts, which is 

 impossible on the basis of the atomic theory as generally ac- 

 cepted. The behavior of !NaCl is clearly diametrically op- 

 posed to that which we should expect according to the theory of 

 electrolytic dissociation. The electrical conductivity of E"aCl 

 solutions increases regularly with the dilution, as table 2 shows. 

 From the character of the boiling-point results it is clearly out- 

 of the question to make even an attempt to compare the dis- 

 sociation as calculated from the molecular weight determina- 

 tions with the dissociation as deduced from the electrical con- 

 ductivity measurements. 



What has been said concerning NaCl applies also to KC1 

 (Table 13), KBr (Table 14) and KI (Table 15.) The molec- 

 ular weights of these salts continually diminish with increase 

 of concentration, finally becoming less than half the theoretical, 

 whereas the conductivities increase regularly with the dilu- 

 tion (Table 2). It is interesting to note the similarity of the 

 behavior of the haloid salts of the alkalies, to which attention 

 has been previously directed in a general way. 



The molecular weight of MgCL, too, decreases with the in- 

 crease of the concentration (Table 16), finally becoming less 

 than one-third the theoretical value. This salt would then 

 have to dissociate into more than three ions, and that in con- 

 centrated solutions. On the other hand the conductivity in- 

 creases with the dilution. It is again clearly useless to at- 

 tempt a comparison of the degree of dissociation as computed 

 from the observed molecular weights and the conductivity. 



What has been stated concerning MgCl 2 applies exactly to 

 BaCl 2 (Table 17), so that further comments about the behavior 



»-The same fact is also demonstrated by the determinations of Landsberger 

 and Biltz — Zeit. anorg. Chem. 17, 452 (1898). 



