IMPROVEMENTS IN AND ADDITIONS TO TELEGRAPHIC, RECEIVING, AND RECORDING APPARATUS
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Thomas James Smith at the Office of
the Commissioners of Patents on the 30th March 1876. A communication
from abroad by the Count Emile Siccardi, of Turin, in the Kingdom of Italy.
THOMAS JAMES SMITH, of the Firm of Robertson, Brooman, and Company, of 166,
Fleet Street, in the City of London, Patent Agents. "IMPROVEMENTS IN AND
ADDITIONS TO TELEGRAPHIC, RECEIVING, AND RECORDING APPARATUS." Commu-
nicated from abroad by the Count Emile Siccardi, of Turin, in the Kingdom of
Italy.
The object of this Invention is the application of the Morse system to submarine
telegraphy, so as to obtain in transatlantic transmissions the same results as those
now furnished by the same system with land lines. This is effected by means of
a new apparatus which is herein-after described, the principle of which is to
transform the ordinary mirror galvanometer into a translating galvanometer. The
distinctive feature of the galvanometer is the employment of mercury to establish
the contact intended to close the circuit of the current of the local pile, which causes
the action of the printing receiver. It is owing to this very sensitive method of
formation of contacts that one is enabled to efficaciously utilize for this object the
extremely feeble currents transmitted along submarine lines.
The translator galvanometer is constructed as follows: At the centre of a
circular galvanometer is a piece in the form of a cross of which the vertical rod is
of aluminium, and the horizontal cross piece of magnetized steel very light and
therefore very thin. The rod is provided with two needles, each provided at one
of its ends with a sharp platinuin point. These points are respectively opposite
to two tubes also of platinum and filled with mercury. It is the contact of the
point of these needles with the mercury which brings about the passage of the
electric current. There are two screws with ivory points, the object of which is to
regulate the oscillations of the magnetized bar. The whole piece oscillates very
freely on its pivots of well-rounded steel upon two patinum beads, inserted into
the ends of two arms of the metallic support. This support is fixed by a screw to
the bottom of the copper box enclosing the whole galvanometer. There is a con-
ducting wire intended to lead the current from the line into the galvanometer;
this wire communicates with the earth; two wires are in contact, one with a
metallic support and also with the magnetized bar and the needles, the other with
the platinum tubes filled with mercury. They are for the object of closing the
local circuit which actuates the bell apparatus or the printing receiver.
A magnet is caused to approach more or less closely to the galvanometer and
serves to recall the magnetized bar to its point of departure at each oscillation, and
Paine 2,77

page_text: at the same time renders it more or less sensible to the influence of the current of
the line.
Two pivoting needles can be arranged interiorly to the galvanometer and placed
rather far apart from one another, in order that no reciprocal influence may be
exerted between them.
It is desirable also that two exterior magnets should each act upon a single
needle separately, so that one needle should act through the passage of the current
of the positive line and the other through the passage of the negative current.
The two tubes filled with mercury effect alternately with their respective needles
the closing of the local current, so that at each oscillation of one or the other needle
the local circuit is closed cither by the positive or by the negative needle. But
the printing receiver being provided with two armatures capable of acting inde-
pendently of one another, it will easily be understood that the movement of one
of these armatures will depend upon the oscillation of the positive needle whilst
the other will depend only upon the oscillation of the negative needle. It is in
this very simple manner that one will obtain points printed to the left and to the
right of the paper band which unrolls from the printing receiver.
As it is impossible to obtain along certain transatlantic cables, for example, that
from Brest to St. Pierre, currents of a greater or less duration, such as would be
necessary to impress points and lines, my translator galvanometer can be regulated
50 that cach current of the line either positive or negative will print one point to
the right and one point to the left of the band of paper, and thus one will be able
to read the despatches impressed in the same manner as they are actually read now
upon the Thomson galvanometer scale from right to left of a zero which is however
variable.
Having recognized that one is obliged to throw upon the cable three or four
currents in the same direction, these currents passing by the Varley condensator
before arriving into the multiplicator of the galvanometer are not of an equal force,
but on the contrary, the first is very strong and those which follow gradually very
feeble, a circumstance only to be attributed to the persistent charge of the con-
densator, and which might very probably occasion adherences of the needle against
the contact of the mercury which would naturally prevent the quantity of signals
sent from being distinguished, it was necessary above all to find a means of
absolutely destroying this possibility of adherences, and the following is a method
for effectually accomplishing this object :-In the same manner that one is sure of
obtaining by the least deviation of the needle a contact of the latter with the
mercury, inore than sufficient for the closing of the local current which should
actuate the printing receiver, one can with this same contact cause
to
pass across
the Varley condensator a local current of a desired force and always of contrary
denomination to the last current arrived through the line; the condensator becoming
thus instantaneously discharged as each current arrived through the line is ready
to receive a fresh current, an arrangement which ensures a constant force of the
current of the line and destroys at the same time all obstacle to the immediate
return of the needles to their point of departure.
Another and still more simple arrangement is as follows:-Instead of printing
by the receiver upon the paper band of points to the right and the left thereof to
represent one set of points the lines and the other the dots of the Morse alphabet
which necessitates that for certain letters several currents of the same denomi-
nation should always be thrown through the cable, it would be simpler to read the
signals by points impressed always upon the same line, so that the lines could be
represented by two points very near together, thus
and the points
"
"
"
a
by points impressed some distance from one another, thus
regulation which it would be casy to obtain after a short exercise of the employées
in manipulation.