XATTRAL PHILOSOPHY. 121 



pressed successively upon the stops corresponding to the signs to be 

 transmitted, and when the needle comes round to that sign it will stop. 

 The needle at the other station will also stop, but not at precisely the 

 same instant. If the person there is in doubt as to the sign intended 

 he has only to place his finger on a stop to arrest the needle at the 

 other station. " It will be understood that by this apparatus the com- 

 munication will assume the nature of a verbal conversation, in which 

 each party can put in his word." 



But instead of resting here, and relying entirely on the correctness of 

 the party receiving the message, M. Siemens has arranged a magnetic 

 printing apparatus, by means of which the message may be as well 

 printed as by a press. This apparatus consists of a vertical shaft sim- 

 ilar to the shaft carrying the needle, and receiving rotary motion by 

 means of similar mechanism, which carries at its upper part thirty hor- 

 izontal radiating arms, set in the same plane at equal distances apart, 

 on the end of each of which arms is a letter in relief These arms are 

 flexible, and as they act like springs, it is sufficient to drive them up- 

 wards against the fillet of paper a little above them, and make them 

 press against it with sufficient force. This paper passes round about 

 half the circumference of a printing roller provided with printing ink, 

 which is only communicated to the paper where the types on the arms 

 strike. By a peculiar arrangement, the printing roller, which is sta- 

 tionary at the moment of printing, is made to turn and carry the paper 

 round a suitable distance for the purpose of producing a blank space as 

 soon as it has received a letter, and a larger space -when a word is 

 completed. The hammer which strikes the letter underneath is so 

 contrived as to do it at the precise moment when this letter stops to re- 

 ceive the blow. 



This is but a mere sketch of the report. In concluding, the com- 

 mittee say that this system, worked with care, " appears to possess in- 

 contestable superiority over all other apparatus of the like nature, and 

 that with regard to speed they are led to believe that it surpasses all 

 other alphabetical apparatus." 



SUBMARINE TELEGRAPH BETWEEN ENGLAND AND FRANCE. 



THE project of constructing a submarine telegraph between England 

 and France, across the Straits of Dover, first announced during the 

 year 1819,* has been in part accomplished. The following descrip- 

 tion of the laying down the wire, we copy from an English Journal : 



At one o'clock the steamer Goliah was ready to start across the 

 Channel, with all the necessary apparatus on board, and a crew of 

 about thirty men. Between the paddle-wheels, in the centre of the 

 vessel, was a gigantic drum, or wheel, nearly fifteen feet long and 

 seven feet in diameter, weighing seven tons, and fixed on a strong 

 framework. Upon it was coiled up, in careful, close convolutions, 

 about thirty miles of telegraphic wire, one tenth of an inch in diam- 

 eter, incased in a covering of gutta-percha the thickness of the little 



* See Annual of Sclent! fie Discovery, ISoO, p. 123. 

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