m 



of tlie substance was obtained from Seidell's Solnbilities of Inor- 

 ganic and Organic snijstances. Tiic solnliiiilies were caicnlated as 

 grams of aidiydrons sniistances per i gram uf water. The sui)stances 

 appear in tlie list in the order of tlieir water of crystallisation, and 

 of their solnltilily. Tiie substances crystallised in all cases in J lo 

 5 hours after the sealing of the tubes. 



Besides these, some 30 lubes wore sealed with sdlutioiis of less 

 supersatnration. They were watched for 'A months, in which time 

 vevy few crystallised. 



From the above tables it will Ih^ seen that no perfectly general 

 deduction is obtainable; but the following fat-ts are oliser\ahle: 



a. Hydrates easily form supersaturated solution. 



b. Supersatnration is common in easily soluble substances. 



c. Also tlie phenomenon is comnum in those STibstances, which 

 easily form big well-defined crystals. 



Phygk'O-chi'iiilrd] Lahoynlnnj. Prettiilciicij CoUe(ii', Cqlcuttit. 



Chemistry. '■'/'I'lnpi'ni/un'-cocfjif-u'iit of coiicluctirif;/ in ulroholic 



sii/ii/ioiis, iinil c.rtciis'hin of KoHLHAUSCH'.s' hjiitothi'.sls /n ti/cohd/ic. 

 solutions^ By Okvi-indra Nath Bhatta(;haryya and Nii.ratan 

 Dhar. (Commuincated by Frof. Krnst Cohen). 



In a former |)aper'), the results of conductivity measurements 

 of ten sodium salts in alcoholic solutions were |)ublished. The mea- 

 surements were carried out at three teiuperatures, and in this paper 

 the values of the tem|)erature coefticiimt of conductivity are calculated 

 and some deductions made from the results. 



If we sup|)0se that the conductivity increases jiroportionally with 

 the temperature, i. e. the conductivity is a linear function of the 

 temperature, we tind the following values for the tem|)erature cocfti- 

 cient of conductivity of the ten sodium salts in alcoholic solutions 

 investigated : (see table p. 374). 



It is evident from the above table that in all cases the value of 

 the temperatui'e coefticient is about 0.024. Now, from the reseai'ches 

 of Bouty") it is seen that the temperature coefticient of fluidity of 

 alcohol is about 0.024 per degree centigrade. Thus for almost all 

 the salts studied, the temperature coefticient of conductivity in alco- 

 holic solutions is etpial to the temperature coefficient of fluidity 

 of the solutions; because the solutions being very dilute, their \iscosities 

 are practically identical to that of the pure solvent, namely alcohol. 



1) Zeitschf. fiif uiiorg. Oliomiu 82, 857 (191 3). 

 "-) Jour, de Physique (2). 3, 351 (1884). 



25 

 Proceedings Royal Acad. Amsterdaia. Vol. XVllI. 



