KAULENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 301 



eons and deductions were without exception aqueous solutions. 

 The non-aqueous solutions known at that time were practically 

 non-conductors of electricity, and in dilute solutions at least 

 they generally conformed fairly well in their behavior to van't 

 HofT's theory of solutions. Indeed, it was not until Kaoult be- 

 gan his famous work on the freezing-points of non-aqueous solu- 

 tions that it was discovered that molecular weights could be cal- 

 culated from the lowering of the freezing-point. 



In view of the facts then known, the idea gradually gained 

 ground in the minds of those holding van't HofT's theory and 

 Arrhenius' auxiliary hypothesis concerning the nature of elec- 

 trolytes, that non-aqueous solutions in general yield "normal" 

 molecular weights for the solutes, and that thev are "of course" 

 non-conductors of electricitv. This notion took root with sur- 

 prising rapidity and the natural result was that investigations 

 of electrical conductivity, of electromotive forces and of elec- 

 trolysis in non-aqueous solutions were entirely neglected. l When 

 in 1895 I had the great privilege of working in the inspiring at- 

 mosphere of Ostwald's laboratory, I upon one occasion asked 

 the genial director of the institute why the electrical conduc- 

 tivity of non-aqueous solutions was not studied, the reply re- 

 ceived was, "Die nicht wdsserigen Losungen leiten ja nicht." 

 So it was hardly a surprise when in 1899 the new edition of 

 Ostwald's Grundriss der allgemeinen Chemie appeared contain- 

 ing on pages 390 and 391 the sweeping, unqualified, italicized 



statement, 



"Jedesmal wenn ein geloster Stoff von den Losungsgesetzen in 

 solchem Sinne abweicht, dass sein osmotischer Druck (oder die diesem 

 proportionate Gefrierpunkts- oder Siedepunkts-andrang) grosser ist, 

 als seinem Molekulargewicht entspricht, so zeigt er auch elektrolytische 

 Leitfahigkeit und umgekehrt." 



It is to be noted that Keychler^s book on physical chemistry— 

 a much less compendious volume, the English translation of 

 which appeared early in 1899 — nevertheless contains a very fair 



*On the other hand it was at once assumed that free ions exist whenever 

 a substance conducts electricity with accompanying chemical decomposition, 

 be that substance a gas, a molten salt, or a solid. 



