R 1 and R2 are relays for receiving the FIG.
The army was moving from west to east, and relays of six horses carried him in the same direction.
At regular intervals a rotating arm on the distributor connects the five keys of each keyboard to line, thus passing the signals to the distant station, where they pass through the distributor and certain relays which repeat the currents corresponding to the depressed keys and actuate electromagnets in the receivers.
The function of the " combiner " in each receiving instrument is so to group the received combination of positive and negative currents that they operate polarized relays in such a manner that the position of the tongues corresponds with the operation of the levers on the transmitter.
A, slip as received on recorder, using ordinary relays for translating on to second cable; B, slip as received on recorder, when interpolator is used at intermediate station, for sending on to second cable; C (four cells through a line, KR=3.6), signals with recorder under ordinary conditions; D, all conditions the same as in C, but magnifying relay inserted between the end of the line and the recorder.
With the adoption of relays the signalling between the subscribers and the exchange became automatic, and, with the introduction of the principle of double and automatic supervision on the cord circuits, it became possible for the operators to tell at any instant the state of a connexion.
The four telephones on a circuit are so wired that the relays 9-- P ..,, connect two of the bells between each wire and fl-- 0 7-..9 *"y earth, and further that one of each pair of bells responds to positive and the other to negative o-- pulsations.
Two years of incessant labor with relays of artisans working steadily throughout the twenty-four hours were required to finish this piece.
Such a leisurely fashion of transacting business soon grew intolerable, and in 1635 a system of relays was instituted which enabled the journey between the two cities to be accomplished in three days, the charge for a letter being 8d.
It has, indeed, been asserted that, if relays of trained assistants are at hand, no one need die of opium poisoning, even if artificial respiration has to be continued for hours or days.
Davila was murdered, while on his way to take possession of the government of Cremona for Venice in July 1631, by a ruffian, with whom some dispute seems to have arisen concerning the furnishing of the relays of horses ordered for his use by the Venetian government.
This arrangement can be duplexed in the way already explained, by providing differential relays and arranging for the outgoing currents to divide differentially through the two relays at each end.
Each transmitter is therefore able to transmit a separate series of positive and negative currents in different combinations; these are distributed, by suitably arranged distributors and relays at the receiving end of the line, into their respective receivers.
The large modern trunk exchanges are equipped with relays and lamps for signalling purposes.
The movements of the shaft are controlled by relays and electro-magnets which operate in response to the action of the subscriber whose telephone is fitted with a 'calling mechanism which, when the subscriber calls, earths the line a certain number of times for each figure in the number of the wanted subscriber.