Left Hand Needle. Right Hand Needle. ll, A. r, E. | l, H. lr, M. lll, B. rr, F. | ll, I. r, N. rl, C. rrr, G. | lll, K. rr, O. lr, D. | rl, L. rrr, P. Joint Action of Both Needles. l, l, R. ll, ll, S. lll, lll, T. rl, rl, U. r, r, W. rr, rr, X. rrr, rrr, Y. r, completed. ll, rr, I understand, or yes. rl, rl, I do not understand, or no. rl, rl, 1. lr, lr, 2. r, r, 3. l, l, 4. rl, rl, 5. lr, lr, 6. r, r, 7. l, l, l, l, 8. ll, ll, ll, ll, 9. r, r, r, r, 0. Mr. Wheatstone does not appear to be aware of all the advantages of this, his latest plan of using two needles and two wires, since some of his signals for the _numerals_, are repetitions of his _letter_ signals, and require four deflections of a single needle, with a pause between the two first deflections, and the two last, and for _some_ other signals he requires as many as three deflections of a signal needle. He has likewise, apparently, for want of simple signals, omitted the letters, J, Q, V, Z. He could with perfect ease, obtain from his two wires and two needles, sixty-four different signals, requiring the time of only two deflections, each, and using but one hand for manipulating four keys, instead of both hands, as in his present plan. The author has demonstrated it by actual experiment. End of the Project Gutenberg EBook of The American Electro Magnetic Telegraph, by Alfred Vail