1902-3.] Mr Manley on Electrical Conductivity of Sea- W ater. 351 
obviated by almost filling the cell with the solution ; but by 
adopting such a course we should do away with one of the chief 
merits claimed for the method, namely, the shortness of time 
required by the contents of the cell for assuming the temperature 
of the surrounding hath. 
The form of the cell employed in this investigation is indicated 
in fig. 1. The cell is constructed from a 
length of almost uniform glass tubing. To 
the lower end is fused a narrow tube 
carrying a tap, bent upwards and ending 
in a capillary ; the presence of this tube 
makes it possible to thoroughly rinse out 
the apparatus with portions of the sea- 
water before charging for the conductivity 
measurement. The lower electrode e is 
fixed, but the upper one e is movable, 
being fused to one end of a glass tube t, 
which just slides smoothly within a second 
tube T rising from the upper end of a 
ground and well-fitting glass stopper S. 
At m a fine index line is etched upon the 
outer tube ; two similar lines, at a distance 
of 10-24 cms. from each other, are also 
etched upon the inner and sliding tube 
which carries the movable electrode e. 
This electrode can be held at any desired 
height by the clamp c which is shown upon an enlarged scale 
(fig- 1)- 
The cell was calibrated with mercury according to the method 
devised by Bunsen ; it proved to have a remarkably uniform cross- 
sectional area, the mean value being 4*965 sq. cms. 
The platinum electrodes were platinised before the cell was used, 
in the manner recommended by Ostwald. 
Fig. 1. 
The Thermometers. 
The thermometers which were used during this investigation 
were graduated to T y of a degree centigrade. The errors of the 
