IMPROVEMENTS IN ELECTRIC CABLE RECORDERS
Year: 1885

page_text: I, MOSES GERRISH FARMER, of the City and State of New York, United States
of America, Electrician, do hereby declare the nature of my invention for
"IMPROVEMENTS IN ELECTRIC CABLE RECORDERS," and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
The subject of my present invention is an instrument for recording electrical
signals and is more particularly designed as a recorder for use with electric cables
or telegraph lines of great length over which it is practicable to transmit feeble
impulses of current. .
The instrument consists mainly of two parts, one of which is an electro-magnetic
device, or its equivalent, that is moved to a certain extent by impulses of current
and the other the device which records such movements. The specific character of
the former may be varied greatly according to the conditions under which it may
be used, as will hereinafter more fully appear. As a means of recording the move-
ments of this device, however, I employ a short length of fine platinum wire
connected with two wires of good conducting qualities that project from the
moving instrument, and a travelling band or strip of red tissue paper which is
carried past the platinum wire, the heat of which leaves upon the paper a whitish
line. I will explain this instrument in its most practicable and useful form by
reference to the accompanying drawings in which,-
Fig. 1, is a view in clevation and part section of the entire apparatus.
Fig. 2, is a detail in cross section of a portion of the moving part, and
Fig. 3, a modification of the form shown in Fig. 1.
The instrument consists of a light tube A of metal or other material, which is
suspended in a vertical position by a filament or thread B. At the lower end of
tube A is a mercury cup C, in the cover of which is an opening a through which
passes a pin b projecting from the centre of the end of the tube A. By this means
the tube is steadied and held in a vertical position.
:
DD are a number of magnetic needles or bars passing through the tube A all in
the same vertical plane, and with their magnetic poles alternating, that is to say, if'
the right hand end of the upper bar is positive, the corresponding end of the bar
next below is negative, and so on.
EE are a series of galvanometer coils arranged in pairs on either side of the
tube A. and supported in such relative positions with reference to the magnetic bars
.. "

page_text: as to form a compound astatic galvanometer. These coils are connected up in series
with the signalling circuit and are stationary, every impulse of current that passes
over the circuit will therefore produce a certain movement of the bars B and of the
tube A the arrangement shown being a more effective one than a single bar or pair
of bars such as is commonly used in instruments of this character, although my
invention is not limited to any special number of coils and bars or armatures.
The upper end of the tube A carries a mercury cup F. From this leads a wire G
of copper, or other good conductor, down through the tube to near its lower end
where it passes out and is carried along a light arm H of insulating material, bent
downward as shown. Another wire K of copper is attached to this arm and dips
into the mercury cup C passing through a curved slot c in the cover of the same.
To the outer end of wires G, K, is connected a short and fine piece of platinum
wire L, which by means of a battery N connected by wires M with the mercury
cups F, and G is raised to a red heat when the apparatus is in use.
O, is a drum over which is drawn a band of colored tissue paper P from a reel P¹.
This paper is carried so near to the platinum wire L that the latter, when hot
produces a light line upon it.
As the wire L is moved from side to side by impulses of current in the signalling
circuit, the line which it traces will afford a permanent record of the signals
resembling the line traced by the syphon recorders heretofore used. The general
character of this line is shown in Fig. 2.
In order to produce the requisite movement of the arm H and wire L other
forms of galvanometer or similar instrument may be used. In Fig. 3, for example,
a modification is shown in which soft iron bars B' surrounded by coils C¹ are used
in lieu of the magnetized steel bars B. The proper magnetic condition of these
bars is maintained by connecting the coils C' up in the circuit of the wire L by
means of mercury cups f, g, carried by the tube A or an independent circuit may
be used for this purpose. In order to maintain the wire L at a proper temperature,
a rheostat R may be used in circuit with it.
I have found that the effect of the heat of the wire L is best indicated upon
pink or red tissue paper of the ordinary kind, the passage of the wire over this
paper destroying the color and leaving a whitish line thereon.
The rotary movement of the tube induced by the influence of currents in the
coils E upon the bars B or B¹ may be confined within proper limits by suitable
stops if necessary.
The advantages of this instrument are that it is simple and effective, no parts
are likely to be disarranged or impaired by use, while it is exceedingly sensitive
and delicate in its operation from the fact that friction between the moving and
stationary parts is practically eliminated.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1st An electrical recorder consisting of the combination of a platinum wire
arranged to be heated by an electric current and attached to the armature support
so as to move therewith, and a band or strip of colored tissue paper adapted to be
moved past the platinum wire as and for the purpose set forth.
2nd The combination with a series of insulated coils, armatures or magnetized
bars and a support for the same capable of being moved by the action of currents
in the coils upon the armatures or bars, of a platinum wire arranged to be electri-
cally heated attached to the support so as to move therewith, and a band or strip
of colored tissue paper adapted to be moved past the platinum wire, all substantially
as described.
3rd The combination with a series of insulated coils, magnetized needles or
bars and a vertically suspended support by which said bars are carried, of copper
or similar wires connected with an electric circuit and projecting from the armature
support, a short length of platinum wire united to the copper wires, and a band

page_text: or strip of colored tissue paper adapted to be moved past said platinum wire, as
set forth.
4th The combination with a series of stationary galvanometer coils, magnetized
bars in position to be moved by currents in the coils, and a vertically suspended
tube carrying said bars, of copper wires extending from said tube, a platinum wire
connected to the copper wires, an electric battery for heating the platinum wire,
mercury cups for connecting the wire with the battery, and a band or strip of
colored tissue paper adapted to be moved past the platinum wire as herein set
forth.