Improvements in Electrolytical Current-directing Devices and Transformers,
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Electrolytical Current-directing Devices and
Transformers,
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by Charles Pollak, of Mainzer Landstrasse,
Frankfurt on the Maine, in the Empire of Germany, Electrician) to be as
follows:-
My foreign correspondent was the first to discover the quality of aluminium,
now generally known, according to which this said metal, when placed in an
electrolytical cell containing an alkaline or neutral electrolyte, will become coated
with a perfectly-insulating layer on being connected to the positive electrode of
any source of electricity, whereas, on the other hand, it offers no appreciable
resistance to the current passing in the opposite direction; that is if the aluminium
electrode be connected to the negative pole of the source of electricity:
This peculiar quality inherent in aluminium has already been utilized by my
foreign correspondent in order to control the direction of an electric current by
the aid of an electrolytic cell of the kind in question.
If, for example, the cell, in which a lead and an aluminium electrode are placed
in an alkaline or neutral solution, be included in a continuous current circuit,
through which accumulators are charged, such cell will act as a security against
return-current, if the aluminium electrode be connected to the negative pole of
the source of electricity. A return-current instantly covers the aluminium
electrode with the insulating layer above referred to, and is thus stopped by the
said layer.
In a similar manner, the cell acts as an alternating current to continuous cur-
rent transformer, if such cell be inserted in an alternating current circuit. Of
the aggregate number of impulses of current, only those which enter through
the lead electrode can traverse the cell all the oppositely-directed impulses of
current are prevented from passing in the circuit, owing to their being stopped
by the aluminium electrode.
All these facts are known and do not constitute the subject of this invention.
In current-directing devices and transformers of the kind described, the defect
has, however, been found, that the hitherto commercially available aluminium is
not of sufficient purity to present in the cell a sufficient resistance to the electro-
lytes heretofore employed.
To remove this disadvantage, is the object of the present invention.
According to this invention, solutions of chromates or soap are used as electro-
lytes for the said cells.
In solutions of this kind the aluminium electrode keeps in excellent condition
and is subicct to but very slight wear.

page_text: The utilization of solutions of chromates or soap in no way necessitate any
alteration in the known arrangement or method of connecting the cell employed
for the purposes in question.
In this 19th day of October 1897.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in Electrolytical Current-directing Devices and
Transformers.
1, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by Charles Pollak, of Mainzer Landstrasse,
Frankfurt on the Maine, in the Empire of Germany, Electrician), and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:—
My foreign correspondent was the first to discover that aluminium, when placed
in an electrolytical cell containing an alkaline or neutral electrolyte becomes
coated with a perfectly-insulating layer on being connected to the positive elec-
trode of pay source of electricity, but that it offers no appreciable resistance to
the current passing in the opposite direction; that is if the aluminium electrode
be connected to the negative pole of the source of electricity.
This peculiar quality inherent in aluminium has already been utilized by my
foreign correspondent in order to control the direction of an electric current by
the aid of an electrolytic cell of the kind in question.
If, for example, the cell, in which a lead and an aluminium electrode are placed
in an alkaline or neutral solution, be included in a continuous current circuit,
through which accumulators are charged, such cell will act as a security against
return-current, if the aluminium electrode be connected to the negative pole of
the source of electricity. A return-current instantly covers the aluminium
electrode with the insulating layer above referred to, and is thus stopped by the
said layer.
In a similar manner, the cell acts as an alternating current to continuous cur-
Of
rent transformer, if such cell be inserted in un alternating current circuit.
the aggregate number of impulses of current, only those which enter through
the lead electrode can traverse the cell, all the oppositely directed impulses of
current are prevented from passing in the circuit, owing to their being stopped
by the aluminium electrode.
All these facts are known and do not constitute the subject of this invention.
la current-directing devices and transformers of the kind described, the defect
has, however, been found, that the hitherto commercially available aluminium is
not of sufficient purity to present, in the cell, a sufficient resistance to the electro-
lytes heretofore employed.
To remove this disadvantage is the object of the present invention.
According to this invention, solutions of chromates or soap are used as electro-
lytes for the said cells.
In solutions of this kind the aluminium electrode keeps in excellent condition
and is subject to but very slight wear.
The utilization of solutions of chromates or soap in no way necessitate any
alteration in the known arrangement or method of connecting the cell employed
for the purposes in question.

page_text: Having now particularly described and ascertained the nature of this in-
vention, and in what manner the same is to be performed, I declare that what
I claim is:―
In electrolytical current-directing devices and transformers in which is utilized
the peculiar property of aluminium, when used as an electrode, of becoming
covered with an insulating layer when the current passes in a certain direction-
the employment in the cell of a solution of chromate or soap as electrolyte for
preventing the aluminium from wearing too rapidly.
Dated this 11th dor of Iul., 1900
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.