1628 
only watched with a sol that had been brought to a suitable dilu- 
tion for this purpose. Indeed the field of vision becomes clearer 
when flowing takes place. But to the value of this result as a 
conclusive’ proof we may offer an objection because on account of 
the after images of the eye, the moving particles appear more elon- 
gated. More convincing would be a weakening of the light-cone by 
sagittal currency, but it is very difficult to realise a cuvette suitable 
for this purpose (See, however, the end of § 6.) 
It should, however, be remarked that at these very small currency 
velocities the particles do not range themselves quite frontally. 
5. Sveppere Cuvette. 
Therefore we followed a course which gave more chance of 
a satisfactory result. We have verified whether under the influence 
of the electric cataphoresis, the particles range themselves parallel 
to the direction of the electric current. For. this was constructed a 
cuvette’) as indicated in fig. 1. 
Gt = aa 
Fig. 1. 
On a microscope slide two glass plates g were fastened ; round these 
plates platinum foil was beaten (the striped part of the figure); a part of 
the channel formed between the glasses was filled with piceine, which 
was then covered with a covering glass d. Before the remaining 
part of the channel was a little pane v cut from a covering glass 
whilst, finally the little cuvette thus formed could be closed with a 
fitting glass lid. On the platinum foils the current of two accumu- 
lators (4 volts) could be brought by means of two copper springs, 
which are pushed up sideways and to which were soldered con- 
ducting wires. 
The cuvette was pasted on a little table resting on the cardioid 
condenser and hence could be moved upwards and downwards by 
means of the accompanying screw (in these experiments the condenser 
itself was not used and therefore covered with a small copper cap 
to protect it from injury). 
The beam of light now could enter through the pane v, the 
1) Vgl, THE SvepBerG, Nova Acta Reg. Soc. Sc. Upsaliensis [4] 2 No. 1, 
blz. 149 (Studien zur Lehre von den kolloiden Lösungen). 
