[Figure 73] represents a top view of the whole apparatus of the receiving station. The fabric, C′, C′, is marked in equal divisions across it, and in six equal divisions, in the directions of its length, thus marking it into squares. Each platinum ring, a, a, a, &c. (when the instrument is not in operation,) is in contact with the fabric at the middle of the squares across the fabric. It will be observed, that the wires ̈1, ̈2, ̈3, ̈4, ̈5, ̈6 are in connection with the battery, Y, and the circuit complete, except at the arms of the needles. Suppose, for example, the arm of the needle, R′, of the wire, C′, is brought up against the stop of the wire, ̈5, at S; the circuit is then closed, and the current leaves the battery, and passes to the electro magnet, (causing the cylinder and fabric to move half a division,) then to the metallic cylinder, d; then through the fabric, c′, c′, resting upon the cylinder, (where it is in contact with the platinum ring, a, of the wire, ̈5,) then to the platinum ring; then to wire ̈5; then to the metallic stop, S; then to the arm of the needle, R′, along its axis to the mercury; then to the wire, I; then to wire, 8, and to the other pole of the battery, Y. Thus a current is passed through the prepared fabric, and a mark produced thereon, in the middle of its square. If the circuit is now broken, the cylinder moves another half division, which will bring the rings to the centre of the squares, ready for the next signal.

But one battery, Y, is used for all the six circuits, formed with the wire, 8; so that, when three of the circuits are closed at the same instant, as will be shown hereafter, the current passes through the three wires of their respective circuits, making each their appropriate mark upon the fabric.

We now proceed to describe the manner of operating with the two instruments, at their respective stations: and, first, we must here designate each needle by its own peculiar mark of reference. Let the two needles upon the wire, A′, be denoted by, A, S and A, T; those of the wire, B′, by B, S and B, T; and those of the wire, C′, by C, S and C, T. It will appear obvious, from the foregoing description, that but one needle of each wire, A′, B′, C′, can be made to close its circuit at the same instant. However, two needles, or three needles of different wires, may close their circuits at the same instant, but no higher number than three. The various combinations of one mark, two marks, and three marks, upon the same row of six cross divisions of the fabric, constitute the characters representing letters.

Fig. 74.

London.—Transmitting Station.

[Figure 74] represents the transmitting station, which may be supposed to be London, and [figure 75], the receiving station, which may be at Birmingham, with four wires extending from station to station, or three only, if the ground be substituted for the wire, D, D″. The wires, D, A, B and C, are supposed to be united with D″, A′, B′ and C′, respectively. Now, if we depress the keys, in the following order, we shall, for each key, have the following deflections of the two needles, belonging to each key.

No.1.
The keys, H, 7,moves the arm, A, S,to the right,A, T, to theleft.
“ J, 7,“ A, S,“ left,A, T, “right.
“ K, 7,“ B, S,“ right,B, T, “left.
“ M, 7,“ B, S,“ left,B, T, “right.
“ O, 7,“ C, S,“ right,C, T, “left.
“ U, 7,“ C, S,“ left,C, T, “right.