IMPROVEMENTS IN GALVANIC BATTERIES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by James Gray at the Office of the
Commissioners of Patents on the 12th July 1883.
JAMES GRAY of 23 West Street, Gateshead, in the County of Durham,"
Photographic plate manufacturer. "IMPROVEMENTS IN GALVANIC BATTERIES"
My Invention consists in the production of an exciting liquid for galvanic
batteries whereby with cheap materials I am enabled to produce a battery of great
constancy, great endurance and giving a large current.
The materials I employ have all been employed before; but the manner of
employing them and the combination produced are new, and the effect obtained
with a given weight or bulk of apparatus greater than has hitherto been obtained.
I employ sulphuric acid, bi-chromate. of potash and nitric acid, and sometimes I
add permanganate of potash.
The method in which I employ the materials is as follows; I take say one fluid
ounce of boiling water and I add excess of powdered bi-chromate of potash
considerably beyond what the water will disolve, I then by degrees add a large
excess of strong sulphuric acid, stirring all the time. The liquid at a certain point
will become turbid muddy or even as I prefer it thick and pasty. I however
continue to stir and continue to add acid until the paste so formed is redissolved,—
the quantity of acid required for the purpose is dependant on its strength,
ordinarily to the one ounce of water about eight fluid ounces of commercial oil of
vitrol will accomplish this object. The effect of using a smaller quantity of acid
in proportion to the water, or or of using a much diluted acid to form the solution
is that part of the salt would crystalize out in cooling, but by using a strong acid,
and in such large excess beyond what is usual I form a solution which does not
part with its salt by crystalization. The bi-chromate of potash in excess as before
described is for convenience in such excess as that after the addition of the .oil
of vitrol there shall be still an undissolved portion, but of course when the
strength of all the materials employed is accurately known the exact quantity may
be beforehand weighed if desired. The forination of this solution is the first stage
in my process. If water be added to this solution it produces a tendency to
crystalize so that in fact if equal parts of the solution and of water be mixed
crystalization is produced and the endurance of the liquid for battery purposes,
were doubled in volume as it is; is. materially reduced; but by the addition of a

page_text: sufficient quantity of nitric acid I prevent, this tendency to crystalize so that if
thereafter water be added and the solution allowed to cool crystalization does not
occur. The proportion of nitric acid required for this purpose of course varies with
its strength, and with the strength of the materials employed: I do not find an
exact proportion indispensible for this result, but I prefer about a fluid ounce of
commercial nitric acid to two fluid ounces of the solution. The effect of the
addition of nitric acid is to produce a flocculent precipitate which I do not remove
from the fluid, but keep suspended by agitation so as to divide it as uniformly as
possible amongst the cells of a battery charged with it.
If desired water may
however be added so as to dissolve the flocculent precipitate and ensure its distri-
bution in this way, or may seperate the precipate froin the solution, and use
the solution in one battery, and the solid precipitate sufficiently moistened with
the solution may be used in the form of a paste to charge batteries which have to
be moved about. The nitric acid has two actions it renders the solution more fluid
and mobile and capable of penetrating the porous cell and at the same time
produces more vigorous action in the battery. If permanganate of potash be used
I add it to this solution.
I use this solution so formed in a porous cell with carbon or platinum, and for
exciting fluid for the zinc plate I use in the outer cell common salt or salammoniac
and water.