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Proceedings of the Royal Society of Edinburgh. [Sess. 
wound in the form of a cone, makes the best electrode. Discs of platinum 
plate, welded to stout wire stems, should not be employed, because electrodes 
of this form were found to be liable to slight deflection by the incoming 
stream of liquid. In one case an error of one part in four hundred was 
traced to this cause. 
Connection with the electrodes is made by running in mercury and 
inserting copper wires. If a little paraffin is melted and allowed to solidify 
above the mercury, the connections become permanent, and the cell may be 
turned upside down without their being disturbed. 
In order to fill the cell with a given solution, a length of fine-bored 
glass tube, bearing a right-angled bend, is attached to a by a rubber tube, 
so that the vertical part dips into the bottle of solution. Suction is 
applied to h by means of a length of thin rubber tubing, so that the 
solution passes through aa' into the cell. A clip on the suction tube 
may be used to prevent the solution running out again. To have h' 
connected to the upper electrode compartment as high as possible is 
important, in order to avoid the inclusion of air when the liquid is made 
to rise through the cell. 
