XT. APPLICATIONS. 373 



1694a. Printing Telegraph, invented by M. II. Jacobi, 

 academician, in the year 1850. Two uniform apparatus for two 

 stations. 



Physical Science Cabinet of the Imperial Academy of 

 Sciences, St. Petersburg. 



1694e. Charge and Discharge Keys (new form). 



Warden, Muirliead^ and Clark. 



1701. Magneto-electric Morse Ink Printing Tele- 

 graphic Apparatus. Geminiano Zanni. 



The above instrument, consisting of the mechanical clockwork as in an 

 ordinary electric Morse apparatus, has in addition a compound magnet 

 arranged -with an induction coil. The motion is given to the coil for the 

 production of the magnetic current by the same clockwork as drives the 

 paper forward; thus dispensing with the use of the voltaic battery. 



1703. Pair of Undernagnetisable Coils, designed in 1866. 



S. Alfred Varley. 



The magnetic needles inside these coils are made of soft, iron rendered 

 magnetic by induction, instead of being made of tempered steel magnetised. 



As the needles are magnetic only by virtue of the permanent magnets in 

 their neighbourhood, the influence of powerful currents, induced by lightning, 

 upon them, can only be momentary ; consequently the telegraphic circuit is 

 not liable to be interrupted by the demagnetisation of the needles, which so 

 frequently occurs in needle telegraphs of the ordinary construction. 



Extract from the Handbook of Telegraphy, by 11. E. Culley, Engineer-in- 

 chief of Telegraphs to the Post Office, 5th edition, pages 199, 200 : 



" The greatest improvement which has been made in the needle instrument 

 is the introduction of an induced magnet of soft iron for the needle in place 

 of the permanent steel magnet." 



1704. Instrument for sending double-curb signals into sub- 

 marine cables. Sir William Thomson. 



This instrument was constructed in 1858, but not completed in time for 

 trial on the transatlantic cable before its failure in the (September of that 

 year. 



1705. Electro-magnet Relay for reaction produced by the 

 magnetism emanating without regulation. Extremely rapid, and 

 produces a novel double effect, something like the cut of a whip. 



M. Guyot d'Arlincourt. 



1706. Belay for Rapid Transmission. 



M. Guyot d'Arlincourf. 



Application of this relay for the transmission into the rapid apparatus. 

 In this same apparatus two other relays called whipcuts discharge the line 

 with each emission of the current. 



1707. Autographic Apparatus. M. Guyot d'Arlincourt. 



Employment of the circular vibration of the branches of a diapason for 

 regulating the working of the apparatus. New correcting system for ascer- 

 taining at once the isochronous action of two apparatus that are not regu- 

 lated perfectly one upon the other. 



