Feb., 1904.] 



KNOWLEDGE cS: SCIENTIFIC NEWS. 



19 



scribers. Sixteen connecting strings allow of 32 subscri- 

 bers being simultaneously connected so as to enable a 

 simultaneous communication between one third of all the 

 subscribers in the case of the switchboard being complete. 

 As soon as a subscriber presses down the calling key of 

 his printing telegraph, the official in charge of the indi- 

 cator board at the central station will be advised by the 

 indicator of the subscriber in question dropping and an 

 alarum being rung, when he will have to put himself in 

 communication with tiie caller, to ask him for the desired 

 connection through a special enquiring apparatus, and 

 connect both subscribers so that their apparatus are 



ready for immediate mutual communication. There is, 

 however, in addition, the possibility of connecting any 

 desired number of subscribers to the same printing tele- 

 graph so as to transmit the same communication simul- 

 taneously to all the subscribers. This is ensured by the 

 subscribers who, as a rule, are connected to the indicator 

 board of the central station, being disconnected from the 

 latter and connected to the transmitting apparatus in 

 question by means of a group switch. 



Similar telegraphic ser\ices from one central station to 

 a certain number of subscribers simultaneously, by means 

 of a so-called ticker, have for some time been used in New 



York, London, and Paris. A similar service has been in 

 operation also in l!renierhavcn,(iermany,for transmitting 

 ship telegrams from one central station to 100 sub- 

 scribers in dilTerent places. It is intended, from' the 

 central station just opened in IJcrlin, to transmit simihir 

 information to a certain number of subscribers, hmiting 

 the service at first to Exchange telegrams, wliich arc 

 transmitted at gi\en hours from the transmitting appara- 

 tus in tile Berlin ICxchange. The same means of com- 

 munication could he employed for transmitting telegrams 

 from a central telegraph oflice, such as Renter's, to a 

 certain number of newspaper offices. In addition, the 

 above central station is intended to secure comnnmication 

 of the subscribers with the central Slate telegraph oflice 

 for transmitting or receiving telegrams through the State 

 telegraph, for which subscribers are charged a rather low- 

 extra fee of so much per word. 



The main feature will, liowevcr, be the diycct iiiiitmil 

 coiuMitnicatiflu between the subscril)ers, and in tiiis respect 

 ]->erlin may boast of having quite a unicjue means of 

 communication. The system has, by the way, neen in 

 operation for some time with great industrial concerns 

 such as the bierlin Aligemeine l'"leklricitats desellschaft 

 and the Siemens and Halskc Company for communica- 

 tion between their \-arious business departments. 



In addition to the type-printing telegraph used in con- 

 nection with the teletyping service described in another 

 note, the Siemens and 1 lalske Company have just brought 

 out another kind of printing telegraph, intended for rapid 

 service. The apparatus is analogous to the so-called 

 automatical telegraph, where an apparatus similar to a 

 typewriter pierces for each letter to lie telegraphed cer- 

 tain holes in a continuous paper ribbon. The latter, on 

 being drawn along through the rotating telegraphic 

 sender, will throw automatically corresponding currents 

 into the line. As the Siemens apparatus is capable of 

 telegraphing 2,000 letters per minute, the telegrams trans- 

 mitted by a large number of officials will be sent on the 

 same wire. Two holes are pierced for each letter, the 

 letter itself being printed immediately above in plain 

 ordinary printing characters. The perforating may even 

 be effected by the public itself. A disc, where the \'arious 

 letters are cut out as in a pattern, rotates at a speed of 

 2,000 revolutions per minute, between a spark gap and a 

 continuous ribbon of photographic paper. Whenever a 

 spark passes in the gap, a silhouette of tiie letter happen- 

 ing to be in front of the gap will be projected on the paper 

 ribbon, which on running through sponges impregnated 

 with developing and fixing liquids, will complete the 

 photographic process. 



