block is soaked in paraffin so hot as to drive all of the moisture out
of the paraffin and out of the pores of the block itself.

The zinc, as is noted from the cut, is in the form of a truncated
cone. It is about two and one-eighth inches in diameter at the base
and two and one-half inches high. Cast into the zinc is a soft copper
wire about No. 12 B. & S. gauge. This wire extends above the top of
the jar so as to form a convenient terminal for the cell.

The porous cup is cylindrical in form, about three inches in diameter
and seven inches deep. The wooden cover is of kiln-dried white wood
thoroughly coated with two coats of asphalt paint. It is provided with
a slot for the carbon and a hole for the copper wire extending to the
zinc.

The electrolyte for this cell is made as follows:

Sodium bichromate 6 oz.
Sulphuric acid 17 oz.
Soft water 56 oz.

This solution is mixed by dissolving the bichromate of sodium in the
water and then adding slowly the sulphuric acid. Potassium bichromate
may be substituted for the sodium bichromate.

In setting up this cell, the amalgamated zinc is placed within the
porous cup, in the bottom of which are about two teaspoonfuls of
mercury, the latter serving to keep the zinc well amalgamated. The
porous cup is then placed in the glass jar and a sufficient quantity
of the electrolyte is placed in the outer jar to come within about one