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SUMMARY OF CURRENT RESEARCHES RELATING TO 
which is then placed over the opening o and attached with a little grease . 
The platinum wires ab , c d, e f then lie in the liquid, which is prevented 
from passing into the borings by the latter being tilled by a cement which 
is not attacked by acids or alkalies. 
l'TGr. 47. 
To prevent the cover-glass from being displaced owing to the dis- 
engagement of gases during the electrolysis, a channel y x (fig. 46) is cut, 
by which they may pass off. 
With medium' power objectives the three wires all come within the 
field of view, but with stronger objectives only one wire can be observed 
at a time. For this reason the thickness of the middle wire has been 
made one-half that of the other two, and this wire in electrolytic experi- 
ments is used as the cathode on which the metal is deposited. 
The apparatus can be used for both qualitative and quantitative 
electrolysis, and for electrophysiological experiments. 
Fig. 48. 
In electrolytic experiments, the metal (copper, gold, mercury, (fee.) 
is deposited on the middle wire, and determined by observation under 
the Microscope or by chemical tests. 
The use of the apparatus for quantitative results is not much insisted 
on by the author. The method consists in measuring the thickness of 
the metallic deposit on the cathode. Fig. 48 represents this cathode 
magnified. If r denote the original radius of the wire, r x its radius after 
