no 
MESSRS. W. DE LA RUE AND H. W. MULLER ON THE 
the vegetable parchment is made to adhere so as to form a cylinder by means of shell- 
lac varnish on the edge of the last layer, of which there are three of one continuous 
piece ; as the shell-lac varnish does not effectually secure the adherence of the vegetable 
parchment (for nothing does it effectually) a few stitches of thread are made at the 
lower end, the interlacing wire preventing the vegetable parchment from unfurling at 
the upper part. The use of the vegetable parchment cylinder is to prevent contact 
between the zinc rod and the chloride of silver ; C is the paraffin stopper perforated 
with two holes, one for the zinc rod to pass through, the other for filling in the liquid, 
the second hole is ultimately stopped by a paraffin plug pp* 
The stand S S', 16^ X 3^ inches and 4-^ inches high, is made of Honduras mahogany 
and holds 20 cells ; it is supported on four ebonite feet f, f,\ inch high ; on the top> 
rail at the right or left corner, for the alternate shelves of the cabinet, is fixed a screw- 
clamp sc supported on a cylinder of ebonite fitted in the stand, the silver wire SW of 
the last cell is inserted between the screw-clamp and this ebonite support, and held 
fast by screwing the clamp tightly into its support. The zinc of the terminal cell has 
also a screw-clamp screwed on it. The zinc terminal clamp of one tray of 20 
cells is connected by a gutta-percha covered wire N, one end being inserted and 
screwed fast into it, and the other end into the clamp sc connected with the silver 
wire of the terminal cell of the adjoining tray. The cells are glass tubes with flat 
bottoms, 5^ inches high and 1-g- inch in diameter ; they pass through holes in the top 
rail and into recesses in the bottom of the stand. When the trays are put together 
a hot iron, like a soldering-bit, is run round the edge of the tube and round the zinc 
rod, this melts a little of the paraffin, making the joint tight and securing the zinc in 
its place. The flattened silver, on which the chloride of silver is cast, of one cell is 
connected with the zinc of the adjoining cell by passing it through the hole in the top 
of the rod, and securing it by pressing in the taper plugy? with a pair of pliers ; these 
wires are 8 inches (20‘32 centims.) long, 0’05 inch (0T27 centim.) wide, and 
0'009 inch (0‘0229 centim.) thick, and weigh each 13'53 grains (0’88 grm.). The 
holes in the stopper for charging the tubes are lightly closed by the insertion of the 
small paraffin plug pp, when the liquid has been inserted. The chloride of silver rodst 
are 2T25 inches (5 ‘4 centims.) long, and 0'3 inch (0'762 centim.) diameter, and 
weigh 200T2 grains (12'97 grms.) ; the vegetable parchment cylinders are 3 - 8 inches 
(9/65 centims.) long, and 0'44 inch (1T2 centims.) diameter. The zinc rods are 
* The zinc rod is procured from the Belgian Vieille Montagne Zinc Company ; the chloride of silver 
rods, cast on the silver wires from Messrs. Johnson and Matthey, Hatton Garden; the paraffin stoppers 
from Messrs. Field, Paraffin W orks, Lambeth Marsh ; the stands from Messrs. Tisley and Spiller, 
No, 172, Brompton Road, who are prepared to supply all the materials, and also to make the battery 
complete; the glass tubes from Mr. Hicks, No. 8, Hatton Garden, and Messrs. Negretti and Zambra, 
Holborn Viaduct. 
f The cast chloride of silver rods and the silver wires for 1366 cells cost £140 3s. 10 d. = 2s. per cell, 
including the labour of casting. 
