( 630 ) 



1 arrived at the tbllowinp,- result : 



The iiiolet'uhir rise of tlie hoiliiig poiiil iiiercased for solutions of 

 NaC^l and KCl from the eoiu-eiitratien ± 0.3 gr. iriol. per J 000 gr. 

 UJ), i)oth towards higher and towards lower concentrations, or in 

 other words, the molecidar rise of the l)oiling point proved to have 

 a minlmiiin valne lying at ± 0.3 gr. niol. For the anhydrous 

 nitrates of K, Na, Ka, Ag and Ph, however, the molecular i-ise of 

 the boiling [)oint proved, quite in concordance with the determi- 

 nations of the vapour tension, to continually decrease with increase 

 of the concentration. 



The method which was the least accurate in appearance, pi-oved 

 lo he able to j)oint out a mistake l)oth in the method of the freezing 

 point and in that of the vapour tension. The first work w^as then 

 to force the micromanometer to greater accuracy by applying some 

 im|)rovenients, and then to repeat the experiments, hi J90J ^) anew 

 series of ex|)eriments yielded really a result wliich <pialitatively 

 harmonized perfectly witii that obtained by means of the boiling 

 point method. Koi- NaCl as well as for ll^SO., a minimum occurred 

 in the moh^'uhir decrease of the vapour tension, lying at ± 0.5 gr. 

 inol. As before KNOg-solutions gave a strong decrease of I with 

 increase of the concentration. 



In the same year KAHLFABKKCi ^) fonnd for solntions of NaCl, 

 KCl, KBr, KJ and MgCÜ^, that the molecular rise of the boiling 

 point increased continually ^vith the concentration for the lirst and 

 the last salt from the concentration =t 0.2 gr. mol. to ± 5 gr. mol., 

 whereas for KCl, KBr and KJ a more oi' less clearly marked 

 minimum was found. 



BiLTZ ') was the first to confirm my results with certainty in 1902. 

 He found a minimum in the molecular rise of the boiling point, 

 not only for KCl and NaCl, but also for FlbCl and I^iCl. His deter- 

 minations of the freezing point of alkali chlorides showed only for 

 LiCl a continual increase of the molecular lowering of the freezing 

 point with the concentration; a minimum was not found, however, 

 for the chlorides of the alkali metals by this method. For LiNO^ 

 and \a\\y Bit.tz found a faint minimum, whereas for the chlorides 

 of the bivalent metals by the cryoscopic way very strongly pro- 

 nounced minima were found, mostly lying between 0.1 and 0.2 gr. 



1) These Proc. IV September 28 IDUI p. 1G3. 



2) Journ. Phys. Chem. 5, 339 (1901). 



s) Zeitsch. f. l^liys. chem. 40 s. 185 (1902). 



