IMPROVEMENTS IN THE MEANS AND APPARATUS FOR GENERATING ELECTRICITY
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Cornelius Varley and Samuel Alfred
Varley at the Office of the Commissioners of Patents, with their Petition,
on the 24th December 1866.
I, CORNELIUS VARLEY, of 387, Kentish Town Road, in the County of
Middlesex, and SAMUEL ALFRED VARLEY, of 66, Roman Road, Holloway, in
the said County of Middlesex, Telegraph Engineers and Contractors, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE MEANS AND
APPARATUS FOR GENERATING ELECTRICITY," to be as follows:-
Our Invention consists in an improved method of developing electricity,
either by mechanical force alone, or by mechanical force in combination with
chemical action.
We construct our apparatus as follows:-We wrap soft iron bars with
insulated wire in a similar way to an ordinary electro-magnet; these bars may
be made U-shaped, and become electro-magnets when the apparatus is in
use; we also construct iron bobbins of such a length that they will pass just
freely between the poles of the electro-magnets and wrap them with insulated
wire.
In constructing the apparatus we prefer generally to use two electro-magnets
and two bobbins; the bobbins are mounted on an axle and revolve between
the poles of the electro-magnets, and are so arranged on the axle that when
one of the bobbins is between the poles of one of the electro-magnets the other
bobbin is between the poles of the other, and vice versa. On the axle
carrying the bobbins there is a commutator, the ends of the insulated wire

page_text: surrounding the bobbins are connected to this commutator, and through it to
the insulated wire of the electro-magnets, forming the whole into one electric
circuit. Before using the apparatus we generally send an electric current
through the electro-magnets; the object of this is to secure a small amount of
permanent magnetism in the direction we wish in the soft iron cores of the
electro-magnets. On revolving the axle the bobbins become slightly mag-
netized in their passage between the poles of the permanent magnets, and as
the electro-magnets are so arranged that the north pole of the one magnet is
opposite the south pole of the other the bobbins are magnetised first in one
direction and then in the other, generating weak currents (corresponding to
the direction in which the bobbins are magnetized) in the insulated wire
surrounding them. The commutator changes the connections of the electro-
magnets at the same time as the magnetism of the bobbins is reversed, and
consequently the electric currents developed in the bobbins always flow in one
direction through, the insulated wire of the electro-magnets. The effect of the
current passing. through. the, electro-magnets is to increase their magnetism
and to magnetize in a higher degree the bobbins when passing between the
poles of the electro-magnets; more powerful currents are now developed in
the insulated wire surrounding the bobbins, which in their turn induce a
higher degree of the magnetism in the electro-magnets; in this way the
magnetism developed on the electro-magnets and the bobbins act and react on
one another, causing the circulation of increasing quantities of electricity.
In constructing this apparatus to prolong the contact between the bobbins
and the poles of the electro-magnets we generally arm the poles of the electro-
magnets or the bobbins with horns of soft iron. We call this apparatus a
magnetic multiplier. In some cases we use only one iron bobbin and make it
oscillate between the poles of two electro-magnets; this we do by mounting
the bobbin on a lever to which motion is communicated by means of an
eccentric or crank, or by any other suitable way.
When we want currents of a definite amount of force for ringing electric
bells, or for working other telegraph apparatus, we prefer to use permanent
magnets, which we construct in the following way :-We take a number of
bar magnets and make a compound horse-shoe magnet by arranging two sets
of them over one another; we connect the north poles of the one set with
the south poles of the other at one end by means of plates of iron placed
between the magnets, and we prevent the magnets from touching those beneath
them at the other end by means of small pieces of iron of the same thickness
as the plates connecting the north and south poles of the magnets at the
other extremity. The bar magnets are now bolted together, a bobbin made

page_text: of iron and wrapped with insulated wire is mounted on a lever, and works
between the poles of the compound magnet. On removing the bobbin from
between the poles of the compound magnet a current is developed in the act
of demagnetization. To prolong the duration of this current be construct two
of these compound magnets and arrange the north pole of the one opposite
the south pole of the other; the iron bobbin now after passing from between
the poles of the one magnet passes between the poles of the other, and a
current of a longer duration is generated. The magnetic multiplier may be
used in conjunction with a galvanic battery, the effect of which is to bring it
into action more quickly.
When we use batteries we prefer constructing them in separate cells, which
we arrange in groups, each group is placed in an acid eight trough, and a
small hole is pierced through the bottom of each cell, so that when the exciting
fluid or acid is poured into the troughs it flows into the cells.
When useing the magnetic multiplier we sometimes complete the circuit
with a large electro-magnet which may be placed near the machine; this acts
as a sort of reservoir or fly wheel to the machine, making the currents more
constant.