146 On the Application of Galvanic Electricity 



system of electro magnets and levers^ is in all respects similar 

 to Morse's Telegraphic Recorder, wliich is the instrument 

 used in the telegraph offices in this colony. By means of a 

 weight and regulating train of clock-work^ a fillet of paper is 

 kept moving between two small rollers at a pretty uniform 

 rate of an inch per second ; and the armatures and levers are 

 so arranged, that, when acted on by the electro magnets, 

 they indent the paper as it runs between the rollers in paral- 

 lel lines, about half an inch apart. The indenting styles are 

 placed in a line perpendicular to the margin of the fillet, so 

 that if the action of the two electro magnets be coincident, 

 the two indentations will be exactly in ths same point with 

 relation to the length of the paper. The clock-work is wound 

 up by a key, but there l3eing no maintaining power, this can- 

 not be done during the working of the apparatus. The regu- 

 lation of the train is attained by a simple '' fanfly," and can 

 be stopped at any moment by means of a catch pressing 

 against the fly arbor. The ciock--work will run regularly for 

 a quarter of an hour. 



The voltaic circuits, for working the electro magnets, are 

 two : the clock circuit, and the observing circuit. 



The observing circuit is thus arranged, a battery of three 

 cells of Daniel's or Smee's combination being generally used 

 for producing the currents. From one pole of the battery a 

 wire is led to one terminal of the electro magnet of the cir- 

 cuit, from the other terminal a wire is led to the purs of the 

 transit instrument, and then up the side of the purs to wooden 

 frames fitting round them, where it is connected with an in- 

 sulated portion or anvil of a small telegraphic key ; a wii'e 

 attached to the other portion, or hammer of the key, is led 

 to the opposite pole of the battery, and thus, with the excep- 

 tion of the interval between the hammer and the anvil of the 

 key, the circuit is complete. A slight pressure of the finger 

 on the key will complete the cii^uit, when the electro magnet 

 attracting the armature, causes the style to indent the paper. 

 The indentation, when the paper is in motion, will be in the 

 form of a clot or a stroke, as the pressure on the key is mo- 

 mentary or prolonged. The keys are so arranged that in 

 whatever position he may be observing, there is always one 

 convenient to the right hand of the observer. 



The clock circuit, which includes the astronomical clock, 

 is double, in consequence of the necessity of introducing 

 what is known as a relay magnet, Avhose office will be pre- 

 sently described. 



