A Photographic Telegraph Recorder.
Year: 1895

page_text: Date of Application, 14th May, 1895
Complete Specification Left, 13th Feb., 1896-Accepted, 21st Mar, 1898
[Communicated from abroad by LA SOCIÉTÉ INDUSTRIELLE DES TELEPHONES,
of 25 Rue du 4 Septembre, Pans, and CLEMENT ADER, of 68 Rue de
l'Assumption, Auteuil, Paris, France.]
A Photographic Telegraph Recorder.
1, JOHN 1MRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Consulting Engineer and Chartered Patent Agent, do hereby
declare the nature of this invention to be as follows :—
of
According to this invention the pole pieces of a powerful permanent or electro-
magnet are presented towards each other so that their faces are very near each
other, and these faces are of great length so that between them there is a long and
powerful magnetic field. In this field is stretched a fine baie wie, which may be
I copper but preferably is of silver, connected at its oue end to the telegraph line,
at the other end to carth or a retuin line. Each of the pole pieces has at the
middle of its length a notch in which is fixed a screen unmediately behind the wire,
this screen having through it a narrow slot at right angles to the wire. In front
of the wire is a lamp from which by means of suitable lenses or reflectors light 19
directed through the slot on to a strip of sensitised paper which is caused to travel
behind the slot in a direction parallel to the wire.
The apparatus being arranged in a room darkened or having a dark red
illumination, according as positive or negative currents traverse the wire it 18
deflected to the one side or the other interrupting parts of the light which passes
through the slot, so that the paper strip which is led from the instrument through
suitable developing and fixing media, presents its surface all darkened except a
and constitutes
white undulating line which results from the movements of the wire,
a record of the signals transmitted through it.
ABEL & IMRAY,
Agents for the Applicant.
А глoшгаршо голодари м
I, JOHN IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Consulting Engineer and Chartered Patent Agent, do hereby
declare the nature of this invention and in what manner the same is to bo
performed, to be particularly described and ascertained in and by the following
statement:-
According to this invention the pole pieces of a powerful permanent or electro-
magnet are presented towards each other so that their faces are very near each
other, and these faces are of great length so that between them there is a long and
powerful magnetic field. In this field is stretched a fine bare wie, which may be
of copper but preferably is of silver, connected at its one end to the telegraph line,
at the other end to earth or a retua line. Each of the pole pieces has at the

page_text: middle of its length a notch in which is fixed a screen immediately behind the
wire, this screen having through it a narrow slot at right angles to the wire. In
ont of the wire is a lamp from which by means of suitable leuses or reflectors
light is directed through the slot on to a strip of sensitised paper which is caused
to travel behind the slot in a direction parallel to the wire.
The apparatus being aanged in a 100m darkened or having a dark red
illumination, according as positive or negative currents traverse the wire it is
deflected to the one side or the other, interrupting parts of the light which passes
through the slot, so that the paper strip which is led from the instrument through
suitable developing and fixing media, presents its surface all darkened except a
white undulating line which results from the movements of the wire, and constitutes
a record of the signals transmitted through it.
The accompanying drawing shews the arrangement which I employ for carrying
out the above described invention.
Fig. 1 shews a front elevation Fig. 2 a plan, and Fig. 3 a section on line 3-3
Fig 1.
Fig. 4 shows a perspective view of the principal parts to an enlarged scale.
NS are the pole pieces of a powerful permanent or electro magnet A, they are
very long and narrow and are placed very near together. For the sake of clearness
they are shewn much farther apart than would really be the case, the distance
being only just sufficient to allow of the necessary movement of the stretched wire.
The opposite surfaces of the pole pieces are coated with varnish, in case of cout.act
of the wire.
Between these pole pieces the entire magnetic field is concentrated;
at the muddle of their length are formed slots B B' for the reception of the other
parts of the apparatus. The length of the magnetic field may vary from 0.1 metre
to 0.5, or even more.
A very fine uncoated wire C of copper, silver, or aluminium, 18 hold stretched
in the space between the pole pieces, being held by tension screws and nuts t, in
the middle of the magnetic field. It is only blackened at the point where it crosses
the shit of the screen R. The electric current coming from the telegraph cable
enters the apparatus at X and passes through the wire C to earth at T; according
to the well known laws and the action of magnets on electric ourronts, the wire will,
on the passago of the current, be forced out of the magnetic field either to the
right or to the left, according as the current 18 positive or negative. The ſooness
of the wine will have the twofold effect, firstly, of furnishing the necessary resistance
to the passage of the current and secondly owing to its great lightness, its inertia
will be insignificant, allowing of very rapid movements. In the siphon recorders
the moving bobbin and the siphons weigh from 1 gramme to 3 gr., according to the
delicacy of the instruments. The above described wire on the other haud will only
weigh about 1 to 2 milligrammes, that is to say, one thousandth part of the weight
of the siphon recorders, and as its resistance will be just as great as that of tho
bobbins of the latter and as it oscillates in a magnetic field just as strong, the
movements will be much more rapid and almost instantaneous, and the brake action
for limiting them will be supplied entirely by the resistance of the air.
The screen R is painted black; the slit which is at right angles to the wire, is
made of a length equal to the width of the band of photographic paper, and it is
made very narrow, its width being the smaller, the greater is the sensitiveness of
the band. The screen cau be accurately adjusted in position by means of suitable
adjusting screws, not shown.
Lenses L made convex in the vertical direction and straight in the horizontal
dnection, concentrate the luminous rays coming from a lamp in a line extending
along the whole length of the slit f; for producing an effective direction and
concentration, two or more lenses or mirrors may be used if necessary.
The entire optical apparatus is enclosed in a casing so that no rays of light issue
except through the slit.
The sensitized band of paper D is made to travel over a cylinder Y, which is
capable of adjustment to or from the screen R, which however it dous not touch;

page_text: it is drawn off the reel U and is passed with a uniform continuous motion over the
cylinder Y so as to be presented to the slit, and to be actel upon by the concen-
tiated rays of light passing through it, with the exception of the part which is
momentarily obscured by the shadow thrown by the wire C.
This shadow will shift at every movement of the wire when the current is passing
through it, and consequontly, tho consecutive natiow obscurations being thus
photographed upon the band as this travels along, there will be produced a
continuous irregular white line upou the black or dark ground of the band, which
will constitute the signals transmitted. As the band travels along after receiving
the photographic impression, it is caused automatically to pass through several
developing and fixing baths Z, as shewn to a smaller scale at Fig. 5. The operation
is of course carried on in the dark or with a dark red light.
If it be desired to have a black line on a white ground instead of the reverse as
above described, there would be placed in front of the band D a screen E, Fig. 6,
of elder pith having a small hole, and carried by two stretched wires C C¹, instead
of one, through both of which the telegraphing current is made to pass in the same
direction, as indicated by the arrows and which are situated in the magnetic field
so as both to be acted upon as above described. The advantage of having a black
line on a white ground is however more than balanced by the inconvenience of the
adjustment and regulation of two wires instead of one and of the screen carried
thereby, and by the greater weight of the moving paits.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A photographic telegraph recorder consisting of a stretched, uncovered, very
thin wire through which the telegraphing current is made to pass and which is
situated in a narrow space between the pole pieces of a magnet, whereby it is
deflected to one side or the other according to the nature of the electrical impulses
passing through it, such movements being recorded upon a travelling sensitised
band, either by causing the moving shadow of the wire to be projected by rays of
light passing through a narrow slit on to the sensitized strip, or by combining with
two such stretched wires a light screen having a small hole, through which a
moving ray of light is projected on to the sensitized band, substantially as
described.
Dated this 13th day of February 1896.
ABEL & IMRAY,
Agents for the Applicant.