214 PROCEEDINGS OF SECTION B. 
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solidified, on cooling, to a solid x jelly, and was then used. 
The latter material worked more satisfactorily, being stronger 
both ir acid and in gelatine ; but the results obtained were simi- 
lar with both. The tube used was 12 cm. long and 6.9 mm. in- 
ternal diameter. The cell solutions were Cu SO, and K, Cr Oy, 
and the other arrangements were as described in the first part 
of this paper. 
The results were striking; for, while the yellow chromate 
indicator advanced as usual, and with a quite clear-cut boundary, 
there was hardly any corresponding advance of the blue copper 
from the anode end of the tube. In one experiment the tube was 
under observation for more than three hours, and the position of 
the yellow boundary at the end of this time was 10 cm. from its 
starting point, or the rearmost Cl had got to within 2 cm. of 
the anode end of the tube. In the same time the blue colour 
had penetrated only a few mm. in the opposite direction, and 
what there was of it was without any properly defined boundary. 
Practically, therefore, the transport was in one direction only, 
namely, in the direction of the chlorine migration ; and this con- 
clusion was supported by the fact that the observed velocity in 
this single direction agreed well with the total average velocity 
as calculated from the galvanometer observations and the known 
strength of the acid jelly and the cross section of the tube. 
Although further experiments are desirable before any certain 
inferences can be drawn, the following provisional explanation 
may be offered of the observed facts. If the jelly contained 
H Cl as such, i.e., H and Cl ions, much the greater share of the 
transport should be from anode towards cathode, for all known 
facts point to H having a specific velocity nearly five times that 
of Cl. The jelly therefore did not contain H Cl but the chloride 
of some very complex organic base, whose positive radicle was 
unable to travel through the jelly with any appreciable velocity. 
The current must, in such a case, consist entirely of a procession 
of negatively-charged chlorine atoms, followed by chrome ions, 
past positively charged but stationary organic groups. And 
such a case is merely the realisation of the extreme instance of 
the Hittorfian principle of unequal velocities. 
In support of this view of the case, it may be pointed 
out that various proteids have the power of combining with 
acids and alkalis to form compounds of a saline character, and 
that there are good reasons for regarding such proteids as weak 
bases or acids. They themselves, in accordance with this 
character, have practically no ionisation tendency, or they 
may be called non-electrolytes; but the salts they form with 
strong acids or alkalis ionise well. It is not difficult to under- 
stand that either gelatine itself or some complex product of its 
hydrolysis behaves in this way, so that what purports to be a 
solution of acid in jelly does not really contain free acid until 
