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Chemistry. — " Vc/ocï/i/ of ians (tl O' CV' By Devendka Kat» 

 BHAïïACHAinYA uiitl NiLiiATAN DiiAU. (Coniuiuiiicated by 

 Prof. Ernst Cohen). 



From time to time attempts liave heeu maile to determine atrii- 

 rately llie mobilities of ions at 0°. lint liiere is no systemalic work 

 in this line ; only isolated cases liave been investigated. Even the 

 velocity of hydrion at 0° is uncei'tain. An exact idea of onr very 

 much incomplete knowledge would be obtained from the following 

 summary of the work previously done. 



Wood ') was the first investigator in this line. Het determined the 

 molecular conductivities of sodium chloride, potassium chloride, 

 dichloracetic acid, and trichloracetic acid at 0°, and at various 

 dilutions. But his measurements are inaccurate as will be shown 

 subsequently. Archibald 'j, Barnes ') and Kohi.rausch ') also studied 

 some electrolytes. Whetham *) accurately determined the conductivi- 

 ties of some electrolytes at 0°; but he did not attempt in deducing 

 the velocities of individual ions at 0° from his measurements. 

 Kahlenbkrg "), and .Jones and his pupils') also studied some cases, 

 but their measurements are not accurate. The measurements of 

 NoYiis and Coolidge ") agreed with those of Whetham. Evidently 

 no systematic work is done in this line. 



The ionic mobilities of \ari()us ions are fairly accurately known 

 at 18" or at 25° (Noyes and Falk — .1. Amer. Chem. Soc. 33 

 (1911), 143B). But the value for hydrion (H°) is not exactly certain 

 even at 18° or 25°. Ostwai.d ") first used the value 342 at 25°, and 

 then raised it to ."MT in Lehibuch der Chemie 1893, 2, 675. Kohl- 

 rai'sch's'") provisional \alue was 318 at 18° or 352 at 25°. Until 

 recently, these values were accepted. Noyes''), and then Noyks and 

 S.\mmet'') obtained the unex|>ecledly high \alue of 365 at 25°. Rotii- 



I) Phil. Mag. 1896 (5) XLI, 117. 



-) Trans. Nov. Sco. Inst. Sci X, 33, 1898. 

 S) ibiil X, 139, 1899. 

 *) Ann. Phys. Ghem. 1898, 66, 785 -ö25 

 5) Phil. Trans. I'JUO. 



Proc. Roy. Soc. 71, 3.>4 (1903). 

 «) Journal. Phys. Chem. 5, 339 (1901). 



') Amer. Ghem. Journ. 25, 8i9 (1901); 26, 428 (1901); 34, 537 (1905). 

 S) Garuegie Institution Publications 63, 47 (1907). 

 ») Zeit. Phys. Ghem. 1888, 2, 842. 

 1») Leitvermögen der Eleklrolyte pp. 107-110, 200. 



II) Zeit. Phys. Chem. 1901, 36, 63-83. 

 12) Zeit. Phys. Chem. 1903, 43, 49. 



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