638 
CHEMISTRY: LEWIS AND MINE 
TABLE IV 
din V 
dN 
d In R 
dN 
(obs.) 
/ d In R \ 
\ dN ) 
Lithium. . 
Sodium. . . 
Potassium 
-0.534 
-0.014 
+0.643 
-4.70 
-0.12 
+5.66 
-0.82 
+0.92 
+2.73 
+3.88 
+1.04 
-2.93 
It is evident that when added at constant atomic volume lithium 
would increase and potassium decrease the resistance of mercury, the 
very reverse of that which happens at constant pressure. The paral- 
lelism between the figures of the second and the third columns is strik- 
ing; we need not, however, consider the change in volume and the 
change in resistance to be directly related as cause to effect, but rather 
we shall regard them as concomitant effects of some condition in the 
immediate neighborhood of the dissolved particles, a condition which 
probably is closely connected with what is known as the solvation of the 
dissolved metal. The amount of this solvation or combination with the 
solvent undoubtedly increases in the same order as the electrical re- 
sistance, being least in the case of lithium and greatest in the case of 
potassium. Thus, to cite one of the most direct pieces of evidence, it is 
shown by Lewis and Keyes^ that the heats of solution in mercury of 
lithium, sodium, and potassium are respectively 19,600, 19,800 and 
26,000 calories. 
In drawing attention to the difference between the phenomenon of 
conductivity in dilute amalgams and in dilute electrolytic solutions, it 
is only just to remark that, since we are considering solutions in a 
solvent which is itself a good conductor, the case is not entirely anal- 
ogous to that of salts dissolved in a poor conductor like water, but 
rather to a solution of a salt in another molten salt, a system which 
has not as yet been intensively studied. 
iKraus, /. Amer. Chem Soc, 29, 1557 (1907); 30, 653 (1908); 30, 1197 (1908); 30, 1323 
(1908); 36, 864 (1914). 
2 Lewis, Adams, and Lanman, /. Amer. Chem. Soc, 37, 2656 (1915). 
^Bornemann, Metallurgie, 7, 730 (1910); 9, 473 (1912). 
4 Kraus, Physic. Rev., Ser. 2, 4, 159 (1914). 
" Maey, Zs. physik. Chem., 29, 119 (1899). 
^' Bridgman, Proc. Amer. Acad. Arts Sci., 44, 221 (1909). 
^ Landolt, Bornstein, and Roth, Tabellen. 
s Lewis and Keyes, /. Amer. Chem. Soc, 35, 340 (1913). 
