40 J- SAKUEAI : MODIFICATION OF BECKMAXX'S BOILIXG 



Fii ooiiclunoii, a word may be waid with regard to the molecidar 

 weights of iodine and of nidpliur in solution. Paterno and Xasini 

 (Ber. d. Deutsch. Chem. Ges., 21, 2153 [1888]), l^y the method of 

 tlie freezing point depression, found that the molecular weight of 

 iodine in very dilute benzene solutions is represented hy To, whilst it 

 possesses higher vrdiies in more concentrated solutions. They found 

 also that iodine is more or less dissociated into the atomic state in its 

 solution in glacial acetic acid. Loeb (Zeit, phjslk. Chem., 2, 60(i 

 [1888]), however, could not verif}' these conclutions by tlie same 

 method; and, both on account of the small solubility of iodine in 

 either benzene or Macial acetic acid and of the o'reat variations in the 

 results according to concentration, he idtimately gave up these ex- 

 ]ieriments. By determining the vapoiu^ ])ressures of solutions of 

 iodirje in ether and in carlDon l^isulphide, Loel") showed, on the other 

 li;uid, that the molecular magnitude of iodine in lirown etheria.l 

 solutions is represented by I^, whilst in carbon l^isulphide it is less 

 complex and corresponds to the formula lo.j. Lastly, Ijeckmann 

 (^Zett. fi]iysik. Ghein., 5 76 [ISOfl]) found, by the aid of his boiling- 

 method, that no appreciable ditterence exists in the molecular magni- 

 tude of iodirie, whether dissolved in ether or in carbon bisulphide, 

 and that it corresponds to L, in both of the solutiorjs. The numbers 

 he obtained varied between 235 and 25() in etherial solutions, and 

 between 250 and 272 in carl)on Insulphide solutions (1-2 = 254). 

 More recently. Hertz (Zeit, phiisik. Chem., 6, 358 [1890]), by the 

 freezing method, obtained numbers varying between 255.5 and 276,0 

 f<3r the molecular weight of iodine in its dark red solution in 

 naphthalene, and pointed out that the red colour of the iodine solution 

 is not due to the existence of complex molecules, as already shown by 

 Beckmann. My own determinations also fully conûrm the results 

 obtained by the latter. 



