Year: 1886

page_text: Date of Application, 4th Aug., 1886.
Complete Left, 3rd May, 1887.
Complete Accepted, 3rd June, 1887.
I HERMANN ARON, Dr. Philos., of Berlin, in the Kingdom of Prussia, German
Empire, do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in electric batteries, with the view of
obtaining an increased electro-motive power of sufficient constancy, while the battery
is but very little subject to wear and tear, and will continue to work for a considerable
length of time.
Among the great variety of galvanic piles hitherto known, the solubility of zinc
in alkaline salts has repeatedly been realised, but the main obstacle to the successful
use of such piles is owing to the insufficiency of the positive pole hitherto applied.
The best depolarisation hitherto practised has been that obtained from oxide of copper;
the batteries of this kind, indeed, are remarkable for great constancy of power, but
again they are deficient in two essential points. First, the electro-motive power
developed is very small, only about 0.7 volt in the average delivery of current, and
then, traces of the oxide of copper are always soluble in concentrated solutions of the
pile. Thereby copper is brought into contact with the zinc, and local currents arise
there, which particularly with the use of caustic potash, in the course of some length
of time, cause the zinc to be worn out spontaneously and out of proportion.
In consequence I have endeavoured to invent an improved means of oxidation for
galvanic piles of the kind described, and I have succeeded in finding that oxide
of mercury offers great advantages in various respects.
The oxide of mercury is known to give up its oxygen comparatively easily, and
also to be insoluble in alkaline salts; and if in a pile so composed, slight traces
of said oxide enter into solution, they will do no harm, but on the contrary, aid
to obtain the purpose which I have in view. While the traces of copper as stated
before when they enter into combination with the zinc, make local currents arise,
the traces of mercury will amalgamate the zinc and effectively prevent the same from
being attacked, in consequence, the spontaneous loss of zinc will be limited down
to a very minimum of wear and tear.
It must well be admitted, that the oxide of mercury is considerably more expensive
than the oxide of copper, and also that the pile, with oxide of mercury, inferior

page_text: in constancy of action to the other. But against that, the electro-motive power
rendered by the new pile is considerably larger, 1-3 volts, and the constancy of action
is still such, that for a great many applications it is fully sufficient.
For the purpose of increasing such constancy, where it is required, I mix the oxide
of mercury with filings of iron, or other suitable metals, or with small pieces
of carbon, thereby increasing the depolorising surface..
The oxide of mercury may be brought into the pile, either directly in the form
of powder, or it may be prepared within the pile by application of a mercuric salt,
which in the presence of an alkali, gets transformed into oxide.
The difference in the use of oxide of mercury, instead of oxide of copper, in the
pile, is further remarkable by the fact that the oxide of mercury is insoluble, not
only in the mineral alkali, but also in the volatile alkali. In consequence, the caustic
potash or soda of the pile may as well be replaced by ammonium hydrate, which
will only require a small addition, for instance of a mineral alkali, to make the
same conductive.

page_text: Improvements in Electric Batteries.
I, HERMANN ARON, Dr. Philos., of Berlin, in the Kingdom of Prussia, German
Empire, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement :-
My invention relates to improvements in electric batteries with the view of
obtaining an increased electro-motive power of sufficient constancy, while the battery
is but very little subject to wear and tear and will continue to work for a considerable
length of time.
Among the great variety of galvanic piles hitherto known, the solubility of zinc
in alkaline salts has repeatedly been realised, but the main obstacle to the successful
use of such piles is owing to the insufficiency of the positive pole hitherto applied.
The best depolarisation hitherto practised has been that obtained from oxide of copper;
the batteries of this kind, indeed, are remarkable for great constancy of power, but,
again, they are deficient in two essential points: First, the electro-motive power
developed is very small, only about 0.7 volt, in the average delivery of current, and
then traces of the oxide of copper are always soluble in concentrated solutions of the
pile. Thereby, copper is brought into contact with the zinc and local currents arise
there, which, particularly with the use of caustic potash, in the course of some length
of time cause the zinc to be worn out spontaneously and out of proportion.
In consequence, I have endeavoured to invent an improved means of oxidation for
galvanic piles of the kind described, and I have succeeded in finding that oxido
of mercury offers great advantages in various respects. The oxide of mercury
is known to give up its oxygen comparatively easily, and also to be insoluble in
alkaline salts; and if in a pile so composed, slight traces of said oxide enter into
solution, they will do no harm, but on the contrary, aid to obtain the purpose which
I have in view. While the traces of copper, as stated before, when they enter into
combination with the zinc, make local currents arise, the traces of mercury will
amalgamate the zinc and effectively prevent the same from being attacked; in
consequence the spontaneous loss of zinc will be limited down to a very minimum
of wear and tear.
It must well be admitted that the oxide of mercury is considerably more expensive
than the oxide of copper, and also that the pile, with oxide of mercury, is inferior
in constancy of action to the other; but against that the electro-motive power
rendered by the new pile is considerably larger, 13 volts, and the constancy of action
is still such, that for a great many applications it is fully sufficient.
The oxide of mercury may be brought into the pile either directly in the form
of powder, or it may be prepared within the pile by application of a mercuric
salt which in the presence of an alkali, gets transformed into oxide.
The difference in the use of oxide of mercury instead of oxide of copper, in the pile,
is further remarkable by the fact, that the oxide of mercury is insoluble not only

page_text: in the mineral alkali, but also in the volatile alkali. In consequence, the caustic
potash or soda of the pile may as well be replaced by ammonium hydrate, which will
only require a small addition, for instance of a mineral alkali, to make the same
conductive.
I have found, nevertheless, that in electric batteries of the described kind a
spontaneous loss of zinc sometimes occurs in spite of the insolubility of the depolarizing
agent. If such is the case, the action upon the zinc is to be attributed to local
currents arising from heterogeneous parts, which, though insoluble, have been
carried and mechanically brought into contact with the zinc and deposited upon the
same. Such small parts originated from the material of the vessel of the pile,
particularly if the vessel is made of iron; or they may disengage themselves from the
solid, though insoluble matters additionally mixed with the depolarising agent.
To prevent any such heterogeneous parts from coming into contact with the
zinc, f surround the zinc by a coat or cover of finely distributed cotton (wad).
or similar fibrous material, the fibres of which retain all the solid matters floating
within the fluid of the pile and prevent the same from reaching the zinc.
In many cases of practical use, it may be desirable to apply an electric battery
easily portable and ready for use at any moment. To answer such purpose, the coat
or cover of wad which surrounds the zinc may be made of such extent as to fill the
vessel of the pile entirely up. The wad, owing to its strongly absorbing quality,
easily holds a sufficient volume of the fluid to still obtain a greatly constant action
of the battery, though the volubility of the fluid be in some degree diminished.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
First. The application in an electric battery of oxide of mercury in an insoluble
state as a depolarising agent with the positive pole, in combination with zinc and an
alkali forming the negative pole.
Second. In electric batteries having a solid, insoluble depolarising agent at the
positive pole as oxide of mercury, and zinc in an alkali for the negative pole, the
application and combination of a coat or cover of fibrous material, particularly of
wad, surrounding the zinc and serving to prevent any heterogeneous matters floating
within the fluid from coming into contact with the zine, which coat or cover may also
serve to soak up the fiuid of the pile and diminish its volubility, substantially as
and for the purpose described.
D
1
1000