| PUNCTUATION, &c. | |
| Sign. | |
|---|---|
| Full stop | ······ |
| Colon | ---··· |
| Semicolon | -·-·-· |
| Comma | ·-·-·- |
| Interrogation | ··--·· |
| Exclamation | --··-- |
| Hyphen | -····- |
| Apostrophe | ·----· |
| [[6]]Fraction-line | ------ |
| [[7]]Inverted commas | ·-··-· |
| [[7]]Parenthesis | -·--·- |
| Italics or underlined | ··--·- |
| New line | ·-·-·· |
[6]. To be placed between the numerator and denominator of a vulgar fraction.
[7]. To be placed before and after the words to which they refer.
| OFFICIAL SIGNALS. | |
| Sign. | |
|---|---|
| Public message | ··· |
| Official Telegraph message | ·- |
| Private message | ·--· |
| Call | -·-·-·- |
| Correction, or rub out | ···-· |
| Interruption | ········· |
| Conclusion | ·-·-·-· |
| Wait | ·-··· |
| Receipt | ·-··-··-· |
| The length of a dot being taken as a unit, the length of a dash | = 3 dots. |
| The space between the signs composing a letter | = 1 dot. |
| The space between two letters of a word | = 3 dots. |
| The space between two following words | = 6 dots. |
Fig. 287.—Morse Transmitting Key.
Fig. 288.—Morse Transmitting Plate.
Fig. [287] is a view of the Morse transmitting key. A B is a brass lever, moving in bearings at C, and provided at the end of its longer arm with a large knob or button of some insulating material. Steel pins are screwed in at B and D, and they are so adjusted that while that at B is pressed against the projection, E, by the action of the spring, F, when the knob, K, is pressed, contact is broken at B, and established at D. D and E are each provided with a binding-screw, so that wires may be attached in the manner indicated in Fig. [285]. When the key is in the position shown, a current arriving by the line-wire passes from the fulcrum, C, of the lever through the contacts into the apparatus. When the knob is pressed down the battery current enters the lever by the contact at D, and passes into the line from the fulcrum, C. The clerks who are called upon to transmit messages usually soon learn to time the contacts very accurately in accordance with the code of signals, so as to produce the dashes and lines with accuracy. However, with certain persons some difficulty was found in acquiring the requisite uniformity, and to obviate any objection on this score, Morse invented an arrangement for facilitating the signalling, which is represented in Fig. [288]. This is a smooth tablet of a non-conducting substance, such as ivory, except the shaded portions, which are plates of metal having their surfaces even with that of the ivory, and all soldered to a plate of metal beneath the ivory, which places them all in communication with each other and with the binding-screw, C. The lengths of the strips of metal and those of the spaces between them correspond with the dots and dashes of the Morse alphabet as marked on the tablet. The battery wire is connected with the binding-screw, C, and the line-wire terminates in an elastic and flexible coil of insulated wire, which is attached to a short rod having an insulated handle and terminated by a blunt platinum point. This the transmitter takes in his hand and draws uniformly along the line of metal strips belonging to the letter which he wishes to telegraph. The circuit is closed while the point of the style is passing across the metallic strips. This arrangement appears to be but little used, but it is nevertheless admirable for its simplicity, and is described here as a good illustration of the mode in which the varied duration of the contacts is able to produce the signals of the Morse alphabet. With the ordinary transmitting key a clerk is able to telegraph, on the average, twenty or twenty-five words in a minute, but the receiving apparatus is capable of recording three times as many. Morse also invented a system of transmitting the messages automatically, by setting up the message in a kind of type, just as ordinary letters are arranged for printing. The type, if it may be so called, had simple projections like the slips of metal, corresponding with each letter in Fig. [288]. The lines of the message were drawn under a contact-lever, which closed the circuit when lifted up by the projections. Thus the speed of transmission could be very greatly increased, and a single wire and apparatus had its capacity of conveying a great number of messages in a given time proportionately enlarged.