Improvements in Electric Conductors for Carrying Currents of Electric Matter.
Year: 1890

page_text: Date of Application, 11th Oct., 1890
Complete Specification Left, 4th July, 1891-Accepted. 15th Aug., 1891
PROVISIONAL SPEC
Improvements in Electric Conductors for Carrying Currents of
Electric Matter.
I, JAMES JOHNSTONE, Proprietor of No. Merchiston Park, Edinburgh,
heologian, Electrician and Engineer, do hereby declare the nature of this inven-
on to be as follows:-
An improvement of, or an addition to the tubular electrical conductors patented
y Mr. Ferranti in his Patents No. 15,251, Decr. 11th 1885 and No. 2315,
eby. 15th 1888, an example of which he is now laying down between Deptford
nd London.
Fig. 1 is a full sized cross section of the electric conductors now being laid down
Mr Farranti
TRUYIDIONAL
Improvements in Electric Conductors for Carrying Currents of
Electric Matter.
I, JAMES JOHNSTONE, Proprietor of No. 8 Merchiston Park, Edinburgh,
Theologian, Electrician and Engineer, do hereby declare the nature of this inven-
ton to be as follows:-
:-
An improvement of, or an addition to the tubular electrical conductors patented
ly Mr. Ferranti in his Patents No. 15,251, Decr. 11th 1885 and No. 2315,
Feby. 15th 1888, an example of which he is now laying down between Deptford
and London.
Fig. 1 is a full sized cross section of the electric conductors now being laid down
By Mr Farranti
A is empty space.
B is a copper tube * in. thick.
C is half an inch of insulating matter.
D is the outer copper tube
E is insulating matter.
inch thick.
F is a steel tube protecting cover.
This arrangement has two copper tubes to serve as leads for conducting
electricity. The one copper tube conveys the out going current of electricity, the
other copper tube carries the return current of electricity.
Mr. Ferranti's electric conductors as at present laid down are in lengths of
twenty feet. At each join a piece of solid copper of about eighteen inches in
length is fitted tightly into the ends of the inner copper tubes B so that the air is
secluded by itself in each of these twenty feet lengths of tubes. The outer copper
tube D has no air in contact with it, on the contrary it is in contact with insulating
matter both inside and outside of it."
My first improvement on Mr. Ferranti's plan of electric conductors is to construct
the outer conductor of electricity of two metal tubes, an inner and an outer tube,
with an air space between them as shown by Fig. 2, where D, D, are the two metal
tubes and H is the air space between them. These two metal tubes which form
the outer conductor of electricity will be kept separate from each other by a ring
or thimble of metal placed in the space between them at each end, thus coupling
the two tubes into one and thereby secluding the air within the space between them.
The air space both of the inner and outer conductors may be filled with air or any
of the gases at the pressure of the atmosphere, or the air or gases may be rarefied
either by the application of heat or by means of an air pump.
Second improvement. In this I abandon the plan of placing two conductors of
electricity one within the other and use only one conductor as shown by Figure three.
A is the air space, B is the metal tube conductor of electricity, C is the insu-
lating matter, and F is the metal tube for protecting the whole. But in some cases
the external metal tube may be dispensed with, and then the construction of a
conducting main of this kind would no longer be confined to lengthts of twenty feet,
but might be made cables of any required length.
The contents of the air space of this kind of conductor may be treated if required
in the same way as has already been described under my first improvement head.
Dated this 10th day of October 1890.

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Conductors for Carrying Currents of
Electric Matter.
I JAMES JOHNSTONE Proprietor of No. 8 Merchiston l'ark, Edinburgh,
Theologian, Electrician, and Engineer, do hereby declare the nature of this inven
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :—
In the Complete Specification of my Patent No. 15819 of date 7th Oct. 1890
I have referred to the experiments I made in 1839 which led me in that year to
publish that there is only one electricity, and not two as is commonly supposed, and
that electricity is a peculiar kind of matter, and is the ether of the astronomers.
It was the holding of these opinions regarding the nature of electricity, and the
publication of that phenomenon which is now known as the Ferranti effect
which led me to devise the invention herein described.
"
In the Specification No. 15819, A.D. 1890, I have given detailed particulars of
the construction of the electric mains as originally laid, in part, between Deptford
and London by Mr. Ferranti and I have there described the cause of that rise in
the voltage of the current of electricity in those mains, which rise of voltage is now
known as the Ferranti effect," I therefore consider it unnecessary that I should copy
these particulars into this Specification. I will only add that from the Ferranti
mains as originally constructed electricity escaped to earth from the outer tube so
abundantly that the Post Office authorities interfered and Mr. Ferranti was obliged
to alter the insulation of the external part of his mains so that the escape of
electricity from the outer tube no longer existed in its former extent. After this
change was made "the Ferranti effect" ceased to exist, and is now defunct. This
fact shows how worthless the experiments must be which certain parties made with
the view of establishing that "the Ferranti effect" was only an old phenomenon
which had appeared under new circumstances. These experiments were defective
because they were not made under the same conditions of insulation, and other
details which were necessary to be attended to if the experiments were to be of any
value, so as to effect the foundation on which this invention rests.
1 shall now describe my invention and certain improvements on Mr. Ferranti's
Patents No. 15251 Decr. 11th 1885 and No. 2315, Feby. 15th 1888. The drawings
herein referred to are those left with the Provisional Specification.
Fig. 1 is a full sized cross section of the mains as originally laid down by
Mr. Ferranti, and in which the increased voltage called the Ferranti effect
took place.
A is empty space.
B is a copper tube quarter inch thick.
C is half an inch of insulating matter.
D is the outer copper tube one eighth of an inch in thickness.
E is insulating matter.
F is a steel tube protecting cover.
This arrangement has two copper tubes to serve as leads for conducting
electricity. The inner copper tube conveys the outgoing current of electricity; the
outer copper tube carries the return current of electricity.
At
Mr. Ferranti's mains as originally laid down were in lengths of twenty feet.
each join a piece of solid copper of about eighteen inches in length is fitted tightly
into the ends of the inner copper tubes B, so that the air is secluded by itself in
each of these twenty feet lengths of tubing. The outer copper tube D has no air in
contact with it; on the contrary it is in contact with insulating matter both inside
and outside of it.
My first improvement on Mr. Ferranti's plan of mains is to construct the outer
conductor of electricity of two metal tubes, an inner and an outer tube, with an air

page_text: space between them as shown on Fig. 2, where D, D are the two metal tubes,
and H is the air space between them. These two metal tubes which form the outer
conductor of electricity will be kept separate from each other by a ring or thimble
of metal placed in the space between them at each end; thus coupling the two
tubes into one, and thereby secluding the air within the space between them. The
air space both of the inner and outer conductor may be filled with air or any of the
gases at the pressure of the atmosphere or the air or gases may be rarified either by
the application of heat or by means of an air pump.
Second improvement. In this 1 abandon the plan of placing two conductors of
electricity one within the other, and use only one conductor as shown by Figure 3.
A is the air space, B is the metal tube conductor of electricity, C is the insula-
But in some cases
ting matter, and F is the metal tube for protecting the whole.
the external metal tube may be dispensed with, and then the construction of a con-
ducting main of this kind would no longer be confined to lengths of twenty feet,
but might be made cables of any required length.
The contents of the air space of this kind of conductor may be treated if required
in the same way as has already been described under my first improvement head.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed. I declare that what I
claim is
1. Mr. Ferranti's electric conductors or mains are made with only one line of air
vessels in contact with the metal which conveys the outgoing current of electricity.
I make electric mains such as Mr. Ferranti's with two lines of air vessels. The
one set of air vessels being in contact with the metal which conveys the outgoing
current of electricity, the other set of air vessels being in contact with the metal
which conveys the return current of electricity.
2. These air vessels may either contain air or any of the gases at the pressure of
the atmosphere or the air or gases may be rarified either by the application of
heat or by means of an air pump.
3. The making or using of non-concentric mains, or conductors of electricity
having an air-secluding vessel or vessels inside the metal conductor of electricity.
4. These non-concentric, air-secluding, conductors of electricity, or cables may
contain air or gases within them at the pressure of the atmosphere or the air or
gases within them may be rarified either by the application of heat or by means of
an air pump.
T:T: 11 f T... 1801
JAMES JOHNSTONE,
Applicant.