640 



metric metliod ') ; methylene blue was measured by naphtolyellow S, 

 crystalviolet by picrate of sodium and auramine by alcaliblue. 



The adsorption showed to have been increased by the salts in 

 this sequence: 



Methylenehlue B extra 

 [H.O] 'CI "SO, "TO, 'Br 'NO, 



Crystalviolet 

 [H,OJ "'FO, "SO, 'CI 'Br 'NO, 



Auramine O 

 [H,01 'Cl "SO, 'Br 'NO, PO, 



In these series the ion which effects the adsorption is mostly placed 

 at the right. 



5. These results of our first series of measurements indicate that 

 the interpretation must be more complicated than one should think 

 from Pelet's theory. When only the ions of 'CI, "SO, and "'PO, are 

 taken into consideration our results are in harmony with this theory 

 with regard to methyleneblue and auramine, the increasing influence 

 is added to with the basicity of the anions. 



But the 'Br and 'NO, ion already show the importance of lyotropic 

 influence. So we niay draw the conclusion that dyeing is affected 

 by the two sorts of phenomena; — when two ions are of nearly 

 equal lyotropic strength, it will be possible for their electro-adsorptive 

 charactei' to preponderate and therefore to fix the sequence; when, 

 however, there is great lyotropic difference between two ions, this 

 fact will be decisive. With crystal violet the lyotropy of the salts is 

 so predominant that no other influence can be noticed in the sequence. 



An exact interpretation of lyotropic phenomena is always difficult 

 because lyotropy can have so many diffei-ent effects. Even the 

 supposition that the cause of lyotropy is to be found in the power 

 to combine with watermolecules, the so called "solvatation" — 

 though acceptable in many respects — leads to so many consequences, 

 that the explanalion remains totally arbitrary, as long as we 

 cannot verify our theoretical conclusions with many series of expe- 

 riments. We intend therefore to extend our researches to several 

 dyes, electrolytes and adsorbentia. But we may call attention now 

 already to the fact that the importance of lyotropy is not in contra- 

 diction with a theory regarding tlie process of dyeing as a pheno- 

 menon of adsorption, though this complication has remained un- 



1) Bull, de la Soc. Vaudoise des Sc. nat. 43, 1 (1907). 



