with Incandescent Electric Lamps and for other Purposes.
Year: 1885

page_text: with Incandescent Electric Lamps and for other Purposes.
I GUILLAUME ARNOLD NUSSBAUM of 82 Hatton Garden in the County of
Middlesex Civil Engineer do hereby declare the nature of said invention for
IMPROVEMENTS IN RESISTANCE BOXES AND SIMILAR APPARATUS FOR USE WITH
INCANDESCENT ELECTRIC LAMPS AND FOR OTHER PURPOSES to be as follows:-
"
"
This invention relates to improvement in resistances boxes and similar apparatus
for use with incandescent electric lamps and for other purposes and has for object,
to enable such apparatus to be constructed in a more simple, cheap, and reliable
form than has heretofore been usual,
In such apparatus as ordinarily constructed the resistance or resistances employed
is or are composed of a length or lengths of resistance wire, usually of German silver,
wound into coils and connected in series in a manner well understood, one or more
of the said resistances or coils being thrown into circuit, when desired, by a movable
contact strip or finger.
Resistance apparatus thus constructed has several disadvantages, for besides
being costly in material, the construction thereof necessitates considerable care &
consequent expense, and it is liable to damage by the passage of an electric current
of greater strength than that for which the resistance or resistances were originally
designed. Carbon rods have also been employed as resistances but these are liable
to disintegrate and oxidize after being in use a short time.
According to this invention in lieu of employing a resistance or resistances of
the nature above set forth I employ a substance having a composition corresponding
more or less with that of the black lead ordinarily used in black lead pencils
and consisting mainly of a mixture of plumbago or graphite and clay. These
materials are prepared, mixed, and moulded into rods, pencils, blocks or other
desired form for use as resistances, in a similar manner to that adopted for the
manufacture of black lead. Rods etc of this material possess considerable electrical
resistance in a small mass, it is not liable to damage by strong electric currents
even though it be considerably heated thereby and it does not become perceptibly
oxidized even when so heated.
In one form of resistance apparatus according to this invention adapted for use
as a current regulator in conjunction with an incandescent electric lamp or lamps
for the purpose of regulating the candle power or luminosity thereof I employ a

page_text: suitable number of rods or pencils of black lead or the compound substance herein-
before described, mounted within a case or box adapted to hold, and in electric
communication with, an incandescent electric lamp. The rods or pencils (of straight
or curved form) are connected in series by pieces of metal electrically connected
thereto in any convenient manner as for instance by depositing copper upon the
ends of the rods or pencils and then securing the pieces of metal thereto by soldering
or otherwise. A movable contact strip or finger may be employed so arranged that
it may be brought into contact with either of the metal contact pieces for the
purpose of putting one or more of the resistance rods or pencils in or out of circuit
as may be desired, or to cut the apparatus and incandescent electric lamp or lamps
or other apparatus in electrical connection therewith out of circuit; or a second
movable contact strip or finger may be employed for the latter purpose; or the
arrangement may be such that the lamp or lamps or other electrical apparatus may
be shunted, a resistance equal more or less to that of the apparatus shunted being
at the same time placed in circuit.
Apparatus of the kind just described is adapted for use with apparatus for various
electrical purposes other than that of incandescent electric lamps.
As will be evident apparatus according to this invention may be constructed in
various forms adapted for use with electrical apparatus for various purposes such
as volt meters, without departing from the nature of the invention.

page_text: Improvements in Resistance Boxes and similar Apparatus for Use
with Incandescent Electric Lamps and for other Purposes.
I, GUILLAUME ARNOLD NUSSBAUM of 59 & 60 Chancery Lane, W.C. London,
Civil Engineer do hereby declare the nature of my invention for IMPROVEMENTS
IN RESISTANCE BOXES AND SIMILAR APPARATUS FOR USE WITH INCANDESCENT
LAMPS AND FOR OTHER PURPOSES 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 improvements in resistance boxes and similar apparatus
for use with incandescent electric lamps and for other purposes, and has for object
to enable such apparatus to be constructed in more simple, cheap and reliable form
than has heretofore been usual.
In such apparatus as ordinarily constructed the resistance or resistances employed
is or are composed of a length or lengths of resistance wire, usually of German silver
wound into coils and connected in series in a manner well understood, one or more
of the said resistances or coils being thrown into circuit when desired by a movable
contact strip or finger.
Resistance apparatus thus constructed has several disadvantages, for besides being
costly in material, the construction thereof necessitates considerable care and con-
sequent expense, and is liable to damage by the passage of an electric current of
greater strength than that for which the resistance or resistances was or were
originally designed. Carbon rods have also been employed as resistances, but
these are liable to disintegrate and oxidize after being in use a short time.
According to this Invention, in lieu of employing a resistance or resistances of
the nature above set forth I employ a substance having a composition corresponding
more or less with that of the black lead ordinarily used in black lead pencils and
consisting mainly of a mixture of plumbago or graphite and clay. These materials
are prepared, mixed and moulded into rods, pencils, blocks or other desired forms
for use as resistances in a similar manner to that adopted for the manufacture of
black lead. Rods etcetra of this material possess considerable electrical resistance
in a small mass, they are not liable to damage by strong electric currents even⚫
though they be considerably heated thereby and do not become perceptibly oxidized
even when so heated.
In applying my carbon composition as a resistance to be interposed in an
electrical circuit I make use of any of the ordinary forms of resistances, in which
German silver wire or carbon sticks or powder are used, such as the boxes with
short circuiting plugs or switches with a revolving finger pressing on contact plates
as before described. In all cases however substituing my improved resistance
material for that usually employed. In addition to these ordinary forms, the high
specific resistance of my material admits of its employement in forms differing from
those in which it is possible to use a substance or metal in which a great length
and small section must be used to obtain a high resistance. By employing a high
percentage of non conducting material in my composition, I can make a high
resistance having large sectional area and short length and two forms of apparatus

page_text: so constructed and used by me I will now more particularly describe with the aid
of the drawings annexed.
Fig. 1. is a section of one of these apparatus & Fig. 2. a plan of the same.
In fig. 1, A is a hollow carbon rod of my composition, the ends of which are
metal plated or screwed into two metal sockets B, B, screwed on the plate C of
slate or other insulating material. In the inner part of the carbon rod A, is a split
cylinder of metal or carbon D, pressing with a strong spring against the carbon A
and forming a movable contact. When the cylinder D is entirely pushed in it
makes contact with both metal sockets B, B, and the apparatus is thus short circuited.
By moving it from left to right, the resistance of the apparatus increases. This
is placed in circuit with an incandescent lamp and forms a convenient means of
modifying the intensity of the light as may be desired.
Fig. 3, 4 & 5 show another disposition of the same kind of apparatus.
A hollow resistance rod A, of my composition is mounted on a basis of slate or
A metal
other insulating material C, by means of the central bolt, g, and nut a
cylinder D forms the movable contact, it communicates electrically through the
screws bb & bolt g. with the left hand terminal or screw E, the right hand
terminal E¹ is connected with the lower part of the resistance rod, two slots in
the cylinder D at the place where the screws b are, allow the cylinder to slide
up and down.
When the cylinder D entirely covers the resistance rod and rests on the plates G G
the apparatus is short circuited and by moving the cylinder D upwards a certain
length of the resistance rod is introduced in the circuit.
In another form of the apparatus I merely insert my resistance material more or
less into a suitable vessel containing mercury which short circuits the portion
-immersed and so alters the resistance.
Having now particularly described and ascertained the nature of my Inven-
tion and in what manner the same is to be performed, I declare that what
I claim is
1) The employment as a resistance to be interposed in any electrical circuit of
a substance or material composed of an intimate mixture of graphite or plumbago
and clay, in proportions depending on the specific resistance required.
2.) The two forms of resistance apparatus substantially as described and shown
in the annexed drawings.