cities,
as determined from the conductivities, Kohlrausch calculated the
absolute velocities of different ions under stated conditions. Thus,
in the case of the solution of potassium chloride considered above,
Hittorf's experiments show us that the ratio of the velocity of the
anion to that of the cation in this solution is .51 : .49. The
absolute velocity of the potassium ion under unit potential gradient
is therefore 0.000567 cm. per sec., and that of the chlorine ion
0.000592 cm. per sec. Similar calculations can be made for solutions
of other concentrations, and of different substances.

Table IX. shows Kohlrausch's values for the ionic velocities of three
chlorides of alkali metals at 18 deg. C, calculated for a potential
gradient of 1 volt per cm.; the numbers are in terms of a unit equal to
10^-6 cm. per sec.:--

TABLE IX.

+--------------------------------------------+----------------+
| | KCl | NaCl | LiCl |
+---------+-----------------+----------------+----------------+
| m | u + v u v | u + v u v |u + v u v |
+---------+-----------------+----------------+----------------+
| 0 | 1350 660 690 | 1140 450 690 | 1050 360 690 |
| 0.0001 | 1335 654 681 | 1129 448 681 | 1037 356 681 |
| .001 | 1313 643 670 | 1110 440 670 | 1013 343 670 |
| .01 | 1263 619 644 | 1059 415 644 | 962 318 644 |
| .03 | 1218 597 621 | 1013 390 623 | 917 298 619 |
| .1 | 1153 564 589 | 952 360 592 | 853 259 594 |
| .3 | 1088 531 557 | 876 324 552 | 774 217 557 |
| 1.0 | 1011 491 520 | 765 278 487 | 651 169 482 |
| 3.0 | 911 442 469 | 582 206 376 | 463 115 348 |
| 5.0 | | 438 153 285 | 334 80 254 |
| 10.0 | | | 117 25 92 |
+---------+-----------------+----------------+----------------+

These numbers show clearly that there is an increase in ionic velocity
as the dilution proceeds. Moreover, if we compare the values for the
chlorine ion obtained from observations on these three different salts,
we see that as the concentrations diminish the velocity of the chlorine
ion becomes the same in all of them. A similar relation appears in other
cases, and, in general, we may say that at great dilution the velocity
of an ion is independent of the nature of th