Part 7 (1/2)

Midway between the nets and the rear end of the base is a pair of upwardly projecting brackets (C) Between these are pivoted a bar (D), the forward end of which rests between the nets and carries, thereon, a cross bar (E) which is directly above the nets, and serves as the armature

The rear end of the base has a screw (F) directly beneath the bar D of such height that when the rear end of the bar D is in contact therewith the arnet cores (A, A) A spiral spring (G) secured to the rear ends of the arm and to the base, respectively, serves to keep the rear end of the key normally in contact with the screw F

CONNECTING UP THE KEY AND SOUNDER--Having made these two instruments, we must next connect them up in the circuit, or circuits, formed for them, as there must be a battery, a key, and a sounder at each end of the line

In Fig 69 you will note two groups of those instruether There are two line wires, one (A) which connects up the two batteries, the wire being attached so that one end connects with the positive terative ter 69_ A TELEGRAPH CIRCUIT]

The other line wire (B), between the two stations, has its opposite ends connected with the ternet C of the sounders

The other ternet are connected up with one terminal of each key by a wire (D), and to complete the circuit at each station, the other terminal of the key has a wire (E) to its own battery

TWO STATIONS IN CIRCUIT--The illustration shows station 2 telegraphing to station 1 This is indicated by the fact that the switch F' of that instrument is open, and the switch F of station 1 closed When, therefore, the key of station 2 is depressed, a coh wire E' and battery, through line A, then through the battery of station 1, through wire E to the key, and froh wire D, to the sounder, and finally from the sounder over line wire B back to the sounder of station 2, coh wire D'

When the operator at station 2 closes the switch F', and the operator at station 1 opens the switch F, the reverse operation takes place In both cases, however, the sounder is in at both ends of the line, and only the circuit through the key is cut out by the switch F, or F'

THE DOUBLE CLICK--The importance of the double click of the sounder will be understood when it is realized that the receiving operatorif the sounder has transmitted a dot or a dash Whether he depresses the key for a dot or a dash, there must be one click when the key is pressed down on the screw head G (Fig 62), and also another click, of a different kind, when the key is raised up so that its rear end strikes the screw head J This action of the key is instantly duplicated by the bar D (Fig 68) of the sounder, so that the sounder as well as the receiver knows the time between the first and the second click, and by that means he learns that a dot or a dash is made

ILlustRATING THE DOT AND THE DASH--To illustrate: Let us suppose, for convenience, that the doard movement of the lever in the key, and the bar in the sounder, make a sharp click, and the return of the lever and bar make a dull click In this case the ear, after a little practice, can learn readily how to distinguish the nuiven to the key

_The Morse Telegraph Code_

A- N -&

B -O1- -

CP2-

D -Q-3-

ER4- F-S5 - - - G - -T - 6

HU- 7 - -

IV- 8 -

J --W- - 9 -- K -- X-0 ---- ------ L -- Y

M - - Z

EXAMPLE IN USE--Let us take an example in the word ”electrical”

E L E C T R I C A L---- --

The operator first ether; there is then a brief interval, then a lapse, after which there is a sharp click, followed, after a coer interval, with the dull click Now a dash by itself th The short dash is T, and the longest dash the figure 0 The operator will soon learn whether it is either of these or the letter L, which is interth

In tith to the dash iuished In the same e find that R, which is indicated by a dot, is followed, after a short interval, by two dots This le dot for E and the two dots for I, were it not that the ti between the first and second dots, as it ordinarily is between the single dot of E when followed by the two dots of I

CHAPTER X