Five years later Marconi somewhat altered Branly's contrivance, and took out a patent for a coherer of his own.
The coherer is not suitable for use with currents of the intensity required to move a Morse recorder, but it easily switches a powerful current into another circuit.
The intensity coils are common to both; the buried screens are the counterpart of the aerial kites or balloons; the telephone transmitter corresponds to the telegraphic transmitting key; the earpiece to the cohererand relay.
The coherer may be said to resemble an engine-driver, and the "relay" an engine.
The current works a "relay," or circuit through which a stronger current passes, opening and closing it as often as the coherer is influenced by a wave.
In the circuit as shown here the electric waves would cause the coherer to close the circuit and ring the bell.
One end of the coherer is connected to the earth and the other to a vertical wire like that used for the transmitter.
The relay then closes the second circuit, the recording instrument records a dot or a dash, and the tapper strikes the coherer and breaks the filings apart ready for another stream of electric waves.
One of the silver plugs of the cohererwas connected to the receiving wire, while the other was connected to the earth (grounded).
To one plug of the coherer also was joined one pole of the local battery, while the other pole was in circuit with the other plug of the coherer through the recording instrument.
The coherer has been displaced by a new device invented by Marconi, called a magnetic detector, by which the ether waves are aided by a stronger current to record the message.
He elected to spend his leisure time reading up in a text-book, lately issued, an account of the workings of a new coherer that had recently been brought out.
The cohereruntil recently has been spasmodic, until we had Hammond's mercury steel- disc coherer and now my own.
Two rods projecting above the surface of the water receive the waves and are in circuit with a coherer of special type, which affects a relay in the usual way.
The tube of filings through which the electric current is made to pass in wireless telegraphy is called a coherer signifying that the filings cohere or cling together under the influence of the electric waves.
Another form of coherer consists of a glass tube with small carbon blocks or plugs attached to the ends of the wires and instead of the metal filings there is a globule of mercury between the plugs.
The tube of the coherer is generally of glass but any insulating substance will do; a wire enters at each end and is attached to little blocks of metal which are separated by a very small space.
Bose began a study of the whole theory of 'coherer action.
A device for restoring a coherer to its normal condition after it has been affected by an electric wave, a process usually accomplished by some method of tapping or shaking, or by rotation of the coherer.
In a local circuit that is connected to the upright wire in parallel with the coherer is placed a battery, a sounder, or a bell, that is rung when the filings cohere.
It is this current, as it discharges through the coherer to the earth, that causes the filings to unite so as to close the local circuit and operate the sounder.
This coherer is constructed and operated as follows: It consists of a glass tube, of comparatively small diameter, loosely filled with metal filings of a certain grade.
What he seems to have really done was to substitute the cohererof Branly and Lodge, with its adjuncts, for the telephone of Dolbear.
Hughes discovered the phenomena of the coherer and Branby used Hughes's coherer for wireless wave detection in 1892.
The other wire of the coherer is led to the ground, G.
Photograph of the electric lines which emanate from the end of the wire at the sending station, and which are probably reproduced among the metallic filings of the coherer at the receiving station.
The coherer and the motor are shown between two batteries, one of which drives the motor while the other serves to work the bell or sounder when the electric wire excites the iron filings.
W', cause a pulsation in this wire which produces an electrical disturbance in the coherer analogous to that shown in Fig.
He adopted a mechanical arrangement for continually tapping the coherer in order to break up the minute bridges formed by the cohering action, and thus to prepare the filings for the next magnetic pulse.
A delicate coherer will immediately respond to the influence of this pilot spark, and the subsequent oscillations of this discharge will have little effect.
The method of using the coherer to detect electric pulses is not due, however, to Marconi.
We can not depend upon the oscillatory nature of the spark, or adopt, in other words, its rate of vibration and form a coherer with the same rate.
The coherer employed to receive the electric waves.
B is the battery which sends a current through the sounder M and the coherer N when the magnetic whirls coming from the sending wire W embrace the receiving wire W'.
They do, however, possess strength enough to draw the little particles of silver and nickel in the coherertogether in a continuous metal path.
Thus Mr. Kemp knew when he heard the tapper strike the coherer that a signal was coming, though he could not hear the click of the receiver itself.
It continued to ring until he tapped the coherer tube and broke apart the filings.
Using this apparatus now as a transmitter of ether waves, we found that the coherer detected them.
At a given signal (a cough) the confederate made a spark at the spark coil in the other room; this sent ether waves through the partition between the rooms; the ether waves caused the coherer to pass electricity from the dry cell No.
The extra wires which we had attached to the cohererare called antennae, because they suggest the long "feelers" or antennae of some insects.
The coherer or electric eye detected that ether waves were sent forth from an electric bell every time a spark was produced in the bell.
The coherer closed the relay and the relay acted as a push button to close the circuit of the four cells upon the tray.
When the floor wires were connected to the water pipes the coherer would respond when the spark coil was operated in a neighbouring house.
Whenever an ether wave passes the coherer permits the battery cell to send a current around the magnet of the relay, and it attracts the iron spring a, so that it hits against the metal post d with a click.
We now found that the cohererwould respond when the spark coil was operated several feet away.
We now found that the coherer would respond when the spark coil was operated in the farthest part of the room.
One of these wires was stretched out upon the floor, while the other one was connected with the wire of a picture hanging upon the wall on the opposite side of the room from where the coherer was.
The following group of experiments, however, seemed to give the most satisfaction: On a table was placed the coherer connected to the relay, and in another room was placed the spark coil for sending ether waves.
By placing these plugs with their platinum terminals in circuit with a local battery the current from this local battery was given a passage through the coherer by the action of the electric waves coming through the ether.
This is to the wireless telephone what the coherer is to the wireless telegraph.
Marconi further discovered that the most effective arrangement was to run a wire from one terminal of the coherer into the ground, and from the other to an elevated metal plate or wire.
With the Branly coherer as the basis Marconi sought to make improvements which would result in the detector he was seeking.
It would seem that if this theory is true the films must be of a much more refined kind than layers of oxide or dirt, for the coherer effect has been observed with clean non-oxidizable metals.
The sensitiveness of the coherer depends on the electromotive force put in the galvanometer circuit.
Marconi, an Italian physicist, in which Hertzian waves are used in transmission and a coherer is used as the receiving instrument.
The receiving apparatus consisted of another antenna in circuit with a coherer and small battery for operating through a relay the ordinary telegraphic receiver.
Thus far no substance has been discovered with a mechanical responsiveness to so feeble a ray of light; in the world of nature and art the coherer stands alone.
An instant after a signal has taken its way through the coherer a small hammer strikes the tiny tube, jarring its particles asunder, so that they resume their normal state of high resistance.
We have thus a means of comparing the sensitiveness of the retina to light with the responsiveness of the Marconi coherer to electric waves, after both radiations have undergone a journey of miles.
In all likelihood, thecoherer is acted upon in the same way.
The coherer in its present form is actuated by waves of comparatively low frequency, which rise from zero to full height in extremely brief periods, and are separated by periods decidedly longer (Fig.
The coherer and the vertical wire form the essence of the apparatus.
In a homely way the principle of the cohereris often illustrated in ordinary telegraphic practice.
Two rods projecting above the surface of the water receive the waves, and are in circuit with a coherer and a relay.
For instance, the coherer is not as much used as formerly.
One wire from the cohereris connected to the aerial and the other to the ground.
Now, the coherer wires are also connected through a battery to the relay, which in turn is connected through another battery to a Morse register.
If, then, a coherer be brought within the influence of the electric waves thrown out from a transmitter, coherence will occur whenever the key of the transmitter at the distant station is depressed.
The coherer j has two metal pole pieces, j¹ j squared, separated by silver and nickel filings.
The coherer consisted of a small glass tube not more than, say, two inches long by one-quarter inch in diameter, into the ends of which were fused two platinum wires leading to small metallic electrodes.
In the receptor the metallic coherer has been discarded for a magnetic detector.
The filings do not all cling together, but certain chains are formed which afford a conducting path for the current subsequently passed through the coherer from an external source.
In this case the length of the receiving aerial above the point of junction with the coherer circuit is one quarter the length of the wave.
In this case, two lateral wires of different lengths are connected to the receiving aerial, and to the outer end of each of these is connected a coherer tube, the other end of which is earthed through a condenser.
All the receivers of the coherer type and electrolytic type give no indications that are at all proportional to the energy of the incident wave.
It may be well to note at this point the disadvantages that are possessed by any form of coherer as a telegraphic kumascope in connection with proposed arrangements for the isolation of Hertzian wave stations.
The History of the Coherer Principle," and the original title of the work had prefixed to it "Signalling Without Wires.
Accordingly, when the incident electric wave strikes the receiving aerial and creates in it an oscillatory electromotive force, this last will, if of sufficient amplitude, cause the particles of the coherer to cohere and become conductive.
In the original Marconi system, the sensitive tube or coherer was inserted between the bottom of the receiving aerial and the earth.
A variation of the above arangements consists in making this lateral circuit equal in length to one-half of a wave, and connecting the coherer to its centre through a condenser to the earth.
This coherer is connected in between the aerial and the earth, and is also in circuit with a battery and the electromagnet of a telegraphic relay.
The step that led to this addition was taken by Count Popoff in 1895, when he attached a vertical wire to one side of the coherer of the receiver of Professor Lodge, and connected the other side with the ground.
This was in 1894, and the combination of oscillator and coherer actually formed the first real wireless set.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "coherer" in a variety of sentences. We hope that you will now be able to make sentences using this word.
