1839.] 



Telegraphic Signals by induced electricity. 



721 



My first object was to construct a line of wires of sufficient length to 

 afford practically valuable results. With Dr. Wallich's liberal aid 

 a parallelogram of ground, 450 feet long by 240 in breadth, was 

 planted with forty-two lines of bamboos. Each line was formed of 

 three bamboos firmly driven into the ground, fifteen feet in height. 

 Each row was disposed so as to receive half a mile of wire in one 

 continuous line, thus,* 



/ 



The strands of wire were one foot apart from each other. As each 

 row was laid down, it was carefully coated with tar varnish. 



A tent was pitched in front of the entire line, and the connections 

 of the wires were so established that in the course of half an hour it 

 could be tested from centre to the extreme flank, so as to ascertain the 

 effects of lengths of wire, varying from one to eleven miles at either 

 side, forming a total circuit of twenty-two miles. This may be per- 

 haps more readily intelligible from the subjoined figure. 



! 



T 



T 



K 



T T 



y 



u 



7 



7 



2 -3 



t 



7 



t 



T 



I 



Eleven lines should have been shewn in this drawinj 



