20 National Geographic Magazme. 
ately over the centre of a fillet of paper, which is unwound by. 
clock-work. If the siphon touched the paper, the feeble currents 
sent through the cable would be powerless to move it, on account 
of the friction, and in order to produce a mark some means must 
be found of forcing the ink through the capillary tube. This is 
accomplished by electrifying the ink positively and the paper 
negatively, by means of a small inductive machine, driven by an 
electric motor. The effort of the two electricities to unite, forces 
the ink through the tube and it appears on the paper as a succes- 
sion of small dots. When the paper is in motion and the coil at 
rest, a straight line is formed along the middle of the fillet by 
these dots, but as soon as a current is sent through the coil the 
siphon moves to the right or left making an offset to this line. 
These offsets on cne side or the other are used as the dots and 
dashes of the Morse alphabet. A time signal sent over the cable 
while this instrument was in circuit, appeared as a single offset on 
the paper, and it was only necessary to graduate the paper into 
seconds spaces by the local chronometer, in order to have the 
automatic record required. The ordinary chronometer circuit 
could not be put through the coil directly, as it would then 
charge the cable and interfere with the signals, and besides, the cur- 
rent, unless by the introduction of a high resistance it was reduced 
in strength, would infallibly give such a violent motion to the 
coil as to break the siphon, if it did no other damage. ‘The result 
was obtained in this way ; an ordinary telegraph relay was put in 
the chronometer circuit and the armature of course moved with 
the beats. To this armature was fastened one end of a fine 
thread. The other end was attached to a slender piece of elastic 
brass which was fixed at one end to the framework supporting 
the paper, in such a way that the other end touched the metallic 
vessel holding the ink, except when the thread was drawn tight 
enough to pull it away. This the armature of the relay did 
while the circuit through the chronometer was complete, but as 
- goon as it was broken at the beginning of a second, the tension of 
the thread was relaxed and the brass sprung back against the 
ink well, allowing the positive and negative electricities to unite 
independently of the siphon. The ink then ceased to flow, until 
the spring was drawn away, thus leaving a small blank space in 
the line of dots and forming a very good chronographic record. 
This was liable to a small error due to the length of time that 
elapsed between the release of the spring by the armature and its 
