Year: 1886

page_text: I ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
Engineer, do hereby declare the nature of this invention (a communication from
Dr Orazio Lugo of the City, County, and State of New York, United States of
America, Chemist) and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to Galvanic Batteries.
The object is to obtain a constant electrical energy that is to say, constant Volt-
Ampère.
This invention consists in a method of keeping the negative element free from
deposit of other elemental matter, at the same time keeping the solution with
which the negative element is in contact nearly of the same composition as when
at first used.
To carry this invention into effect a cell of two elements is constructed one being
zinc while the other may be carbon; and these elements are immersed in two
liquids the one being alkaline the other neutral.
The carbon element is in a porous cup containing a metallic chloride solution
such as a solution of chloride of copper; or it may contain a mixture of oxide and
chloride of copper in solution.
The zinc element is in the outer jar generally in glass containing a solution of
a caustic alkali such as soda.
The two elements constituting the battery are those in contact with two different.
liquids or solutions.
The current of the battery will remain constant until the alkaline solution in
contact with the positive element (zine) is saturated or until the zinc is consumed
if the caustic solution is in excess.
The electro-motive force of the cell would also remain constant if the contact
liquid of the negative element (the carbon) should not be changed and another
contact element such as copper should be presented. The electro motive force
of the battery would then remain at about 22-10 Volts carbon being the
negative element,

page_text: The amount of current (Ampére) desired to be obtained is in direct proportion
to the surface of each element exposed, whether the negative element be carbon or
copper.
A battery thus composed proved to be constant in current with a constant
external resistance but it cannot remain constant in electro-motive force for the
reason that the carbon element becomes covered with metallic copper thus
proportionally diminishing the electro-motive force of the battery especially after
the chloride of copper is used up by the work which the battery has performed.
In operation the chloride is first formed into a hydrated oxide and then reduced to
metallic copper by the hydrogen liberated at the carbon electrode when all
electrical action would cease, irrespective of the condition of the zinc or other
positive element and of the caustic solution.
The problem therefore is to obtain the constant electrical energy that is to say
constant Volt-Ampère and the desired result is obtained by providing means to
keep the negative element or carbon electrode free from other elements and at the
same time keeping the solution with which the carbon is in contact nearly of the
same composition as when at first employed.
As above stated the action of the battery when in action is to deposit metallic
copper upon the carbon. The chloride of copper is first decomposed, the chlorine
going to the zic and there being formed first zinc chloride and ultimately zincate
of soda or a mixture of soda and oxide of zinc-leaving a hydrated oxide of copper
and metallic copper in the porous cup with the carbon.
But the deposit of copper is obviated as follows:-The carbon electrode is made
in the form of a cup or any other desired form and in it or in contact with it is
placed free hydrochloric acid, when no metallic copper can accumulate or be
deposited on the carbon electrode since it will be immediately dissolved.
In this manner a full carbon contact is preserved and a constant electro-motive
force due to the uniform contact of the carbon element is obtained.
Again as the action of the battery is to deposit copper on the carbon and the
carbon is saturated with hydro-chloric acid this attacks or dissolves the copper as
it is deposited a new supply of chloride of copper is constantly formed (so long as
free hydro-chloric acid is present) thus constantly supplying chlorine to the zinc
and keeping up the action of the battery.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondent I declare that what I claim is:-
1. A galvanic cell in which the negative portion is provided with a separate
substance by which the elemental matter deposited in the action of the battery is
removed substantially as specified.
2. A galvanic cell in which the negative portion is provided with a separate
substance by which the elemental matter deposited in the action of the battery is
removed such substance forming with the removed elemental matter a compound
serving to replenish a portion of the battery.