Popular Science Monthly 



953 



were it not for the difficulty of learning 

 the code sufficiently to understand what 

 comes over the wire. And it is to make 

 possible a line which sends automatically 

 and automatically translates its signals 

 that the device illustrated herewith was 

 developed. 



The principle made use of involves the 

 so-called "step by step" method of pro- 

 ducing synchronous motions at separated 

 points and makes use of the ordinary tele- 

 graph sounders and keys and the ordinary 

 battery. 



Reference to the drawings will show 

 that there is provided a flat wooden wheel 

 having around its periphery forty di- 

 visions to correspond to the forty neces- 

 sary characters of the alphabet including 

 the numerals and the necessary punctua- 

 tion marks. To the shaft of this wheel is 

 rigidly attached a thin metal rachet wheel, 



The wood wheel with a thin ratchet wheel 

 attached to turn it as the sounder works 



such as can be purchased at the store of 

 any gear supply dealer, having forty 

 teeth. This shaft is mounted to rotate 

 rather stiffly between bearings formed by 

 screws having holes drilled in the tips, the 

 shaft being pointed at either end to bear 

 in the holes. The bearing screws are 

 mounted in wood pedestals, as suggested 

 by the drawings, and the whole mounted 

 on a suitable base. A telegraph sounder, 

 or any similar arrangement of magnets 

 and lever, is arranged under the wheel and 

 has mounted at the end of the lever a thin 

 piece of spring metal which is bent so as 

 to form a hook to engage with the ratchet. 

 As will readily be seen this arrangement 

 causes the letter wheel to revolve through 

 the space occupied by one letter every 



time the sounder arm is drawn down. 

 There is also another piece of flat spring 

 metal to prevent the wheel going back- 

 wards and also to press on the ratchet 

 continuously so as to prevent it turning 

 too freely and thus getting out of time. 



From the above description, the use of 

 the apparatus will be plain. There is 

 provided at each end of the line one of the 

 letter wheel machines, a telegraph key 

 and a battery, all connected in series as 

 in an ordinary telegraph line. When one 

 wishes to transmit he opens his key lever 

 and makes "dots" until the letter he 

 wishes comes to the opening in the shield 

 over the type wheel, then he pauses long 

 enough to let the receiver know that that 

 letter is to be copied, then proceeds to the 

 next letter and so on. The end of a word 

 is signified by a space, and the end of a 

 sentence by a period or question mark. 

 The method is, by its very nature, slow, 

 but is quite accurate, which is more than 

 can be said of the ordinary amateur Morse 

 line. After some practice, fair speed can 

 be obtained though. 



Certain refinements naturally suggest 

 themselves to the amateur — such, for 

 instance, as having an extra wire or a 

 duplex circuit to force a strip of paper up 

 against the wheel, which would have 

 rubber type set on it, thus producing a 

 printing telegraph. It is also evident 

 that the line described is a closed circuit 

 line and consequently gravity batteries 

 should be used as the current flows all 

 the time when no message is being sent. 

 This is, of course, the most reliable type 

 of line, but there arc many well-known 

 ways of producing an open circuit line on 

 which ordinary dry batteries may be used. 



Another method requiring a fair amount 

 of interesting developing work is to 

 use low frequency alternating current 

 produced by a magneto generator to 

 operate the apparatus. Thus, when it is 

 desired to send a letter, the key is simply 

 held down till the natural pulsation of the 

 current has brought round the proper 

 letter, when it is released for a moment. 

 This method is entirely practical and well 

 worth the trouble of constructing it. On 

 lines running more than 100 ft. it is very 

 desirable to use relays, as the current re- 

 quired to operate the letter wheels is too 

 much to transmit any distance without 

 serious loss in the line.— Chas. Horton. 



