1 877.] 
Recent Advances in Telegraphy . 
363 
telegraphic receiving instruments. It consisted of a combi- 
nation of resistance-coils and condensers — the resistance- 
coils, of course, imitating the conductor of the cable, and 
the condensers its inductive capacity. Such an artificial 
cable is shown in Fig. 6. The condensers, or accumulators 
Varley’s Artificial Line. 
JUbe^stdi/ 
^ ' to X arch 
6 * 
as they are sometimes called, are regularly distributed along 
the rheostat. The current is made to pass through the 
rheostat or resistance-coils to earth, as through the conductor 
of a cable, and in its passages it charges the condensers, 
which in this come to imitate the induction of the earth. 
Stearns made use of Varley’s artificial cable in his expe- 
riments in submarine duplex. He modified it to a slight 
extent by attaching all the condensers together at one point 
of the rheostat, and inserting resistances between them, so 
as to regulate the charges which they took up. For instance, 
as shown in Fig. 7, he would insert an adjustable resistance- 
coil between the rheostat and a condenser, and another coil 
between two condensers themselves. He had thus a means 
Stearns’s Artificial Line. 
of controlling the charges of the condensers so as to bring 
the artificial line, if possible, into harmony with the cable. 
But experience has shown that such a combination of con- 
densers and resistance-coils does not approximate to a cable 
sufficiently for the purposes of practical duplex working on 
