ix
earliest instrument is thus stated in Cooke’s 2nd vol. (pp. 15 and 17):—
“Within three weeks after the day on which I saw the experiment, I had made, partly at Heidelberg and partly at Frankfort, my first electric telegraph, of the galvanometer form, which is now at Berne. It has been written for and shall be laid before the arbitrators. I used six wires forming three metallic circuits and influencing three needles. I worked out every possible permutation and practical combination of the signals given by the three needles, and I thus obtained an alphabet of twenty-six signals. I had invented the instrument which I called the detector; by means of which injuries to the wires, whether from water, fracture, or contact, are readily traced; an instrument which, in practice, is never out of my hand, and without which the electric telegraph would be impracticable. But my principal improvement was that my telegraph did not merely send signals from one place to another, but that it was even at that early period a reciprocal telegraphic system, by which a mutual communication could be practically and conveniently carried on between two distant places; the requisite connections and disconnections being formed by pressing the fingers upon keys, and the signals being
seeing!”—between believing in the ideal invention and seeing the realization of the idea in Cooke and Wheatstone’s practical telegraph at Euston Square!”—Cooke’s 1st vol. pp. 59 & 158.
