on Osmosis, Solubility, and Narcosis. (alae 
Since the constants of capillarity for isomeric substances 
differ but little, and since moreover the capillarity of the 
_ saturated solution depends chiefly on the constants for the 
pure substance, the more soluble substance must generally 
have the higher constant of capillarity. And this is actually 
the case. As, for instance, with propyl! alcohol and isopropyl 
alcohol ; isoamyl alcohol and dimethylethy] carbinol ; propyl 
aldehyde and acetone; butyric acid and isobutyric acid. 
The connexion between solution-tension and captllarity is 
clearly more close than that between solubility and capillarity. 
Methyl and ethyl alcohols are both equally soluble in water ; 
but the solution-tension of methyl alcohol is considerably 
greater than that of ethyl alcohol. The two can be compared 
quantitatively. 
In the course of former investigations I was able to find 
empirically an extremely simple law,—since corroborated by 
others*. It is that 
Equal equivalents of substances belonging to homologous series 
(ordinary alcohols, fatty acids, esters, Sc.) exercising a strong 
influence on es ity, lower the ee height of water 
in the proportion 1:3: 37: 3°. 
Some new values Ae be here quoted in cine a Sen of the 
law, supplementing those which I have previously given. 
The specimens (supplied by Kahlbaum) were, when necessary, | 
shaken up with soda, and repeatedly fractionated over an- 
hydrous sodium sulphate. 
Concentration 
in equivalents | Capillary height 
of the aqueous | at 18° C, 
solution. | 
UR Ae sinvs ower: saes5%s|' ||) ) | wneseedetane | 92°5 mm. 
Methyl acetate ............... lnormal | 981; 
| Ethyl BCC UAUCR mat asic kes/as cc os 3 ” 58:0 ” 
| Propyl acetate ............... = 9 Dieiie, 
| 1 c 
| Wsobubylacetate /:.......-.. a7” 588 ,, 
Tsoamyl acetate............... = %5 59:9, 
| Heopiiyric acid’ ......5.. 5.0.5. | = ; Oe as 
| 
* I. Traube, Ann. Chem. Pharm. cclxy. p. 27, and Forch, Wied, Ann. 
Phys. |xviii. p. 810 (1899). 
