354 SEC. 10. ELECTRICITY. 



The signals are similar to those of Cooke and Wheatstone's single needle, 

 but the alphabet is different. 



Needle and coil used with this instrument. 



1522. Highton's Needle Telegraph, smaller form. Used 

 by the British and Irish Magnetic Telegraph Company. 



Identical in construction with No. 1521, which it superseded. 



1523. Highton's Needle Telegraph, last form. Used by 

 the British and Irish Magnetic Telegraph Company. 



With key detached. Identical in construction with the two former instru- 

 ments, but 'the signalling key is detached from the indicating portion, and 

 placed near the edge of the desk before the operator for greater convenience 

 of working. 



1524. Key, for Highton's single Needle Telegraph. Also 

 used with Bright's Bell Instrument. 



When the right-hand key is depressed a current in one direction is sent out 

 to the line, and the pointer of the indicating instrument moves to the right. 

 When the left-hand key is depressed a current in the opposite direction is 

 sent, and the pointer moves to the left. 



1525. Bright's Bell Telegraph, 1855, with Belay. 

 Used by the British and Irish Magnetic Telegraph Company. 



The single needle alphabet is produced by striking two bells of different 

 tones, the hammers being actuated by electro-magnets worked by a relay and 

 local battery. The relay consists of two electro-magnetic bobbins placed side 

 by side, their ends being furnished with pole pieces turning inwards. Be- 

 tween these pole pieces at each end of the bobbins the ends of permanentl}- 

 magnetised needles pivoted on vertical axes play ; these needles are so placed 

 as regards their polarity, that a current in one direction moves the needle 

 which closes the local circuit of the right-hand bell, and a current in the 

 opposite direction moves the other needle which closes the local circuit of 

 the left-hand bell. The signalling key used with this instrument is similar 

 to that used with Highton's single needle. 



1526. Bright's Direct Bell Instrument, 1870. (Model.) 



Model of a Bright's bell instrument, in which the bells are struck by 

 hammers attached to the magnetic needles of the relay. 



1542. Relay for Bright's Bell Instrument. 



A relay or repeater for relaying the signals of the Bright's Bell instrument 

 used on the long lines- of the British and Irish Magnetic Telegraph Company, 

 when owing to leakage at the supports, from bad weather or other causes, the 

 direct currents were too weak to work the whole length. In construction it is 

 similar to the relay fixed on the bell instrument itself, but it consists of dupli- 

 cate bobbins and magnetic needles. 



1527. Highton's Gold Leaf Telegraph, 1846. 



A movable conductor formed by a strip of gold leaf is placed in 

 proximity to one pole of a permanent bar magnet, and moves to the right 

 or left of its normal position according to the direction of the current 

 passing through it. It was designed as a substitute for the needle and coil 



