The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

256 DAVY'S ELECTRO-CHEMICAL TELEGRAPH.
c are those which proceed to the receiving station. 1' 2' and
3' are the three batteries, of which P and N are their respective
Fig. 1.
D,..D 7. - _
0 K 3==-=A30
2- Ni 40 ^__ ^
~5 0 50 -
&-6 U7 60 <
poles. The small circles formed at the termination of the wires,
and marked 7, 1, 10, 2, 20, &c., are mercury cups, in which
the terminating wires are immersed. The wires 1 and 20, and
2 and 10, &c., which cross each other, are no in contact, but
perfectly insulated. The wires shown in this figure are all
Fig 2.
C
1 8
9secured permanent, with teir m y cs to oe
secured permanently, with their mercurey cups to one common
base-board. The letters H J K M o and u represent the places
of the six finger-keys used in transmitting signals. There is