_Third plan_, is that using three wires, three magnets, three type levers and the telegraphic characters represented in table second, page 30. The seven first would require one motion each, and the remainder two each. Taking 1177 letters, the motions required to transmit them, would be 1917 + 1177 for spaces, and would equal 3094 motions, which, divided by 1177, would give the average number of motions 2⁷⁴⁰/₁₁₇₇ for each letter, nearly 2⅔, or 85 letters per minute. Cost of wire $6000. _Fourth plan_ consists in using four wires, four electro magnets, four type levers, and the telegraphic characters of the third table. The first sixteen letters require the time of but one motion each; the remainder, two each. Using 1177 letters, the motions required to transmit them would be 1506 + 1177 for spaces, and would equal 2683, which divided by 1177, would give the average number of motions 2³²⁹/₁₁₇₇ for each letter, nearly 2⅓, or 103 letters per minute. Cost of wire $8000. _Fifth plan_, is that of using five wires, five electro magnets, five type levers, and the telegraphic characters of the 4th table. The characters would require one motion each, equal to 1177 + 1177 for spaces, and would equal 2354, which, divided by 1177, would give the average number of motions, 2 for each letter, or 120 letters per minute. Cost of wire $10,000. We now come to the _third_ class, in which 26 types are used, arranged upon the periphery of a wheel, in alphabetical order, and require to be brought to one certain point, where the paper is ready to receive the impression of the type, by another arrangement, distinct from the type wheel and its machinery. Of this plan, is that which has been already described in figures 52, 55 and 56. The estimate is there carried out, at 4 motions per second, gives 36⅔ letters per minute. Cost of wire $2000. The following table will show the comparative value of these various methods: Letters per Cost. Number of On Morse’s No. minute. wires. plan. 1st Class. { 1st plan, 480 $26,000 13 780 1 { 2d “ 240 26,000 13 780 2 2d Class. { 1st plan, 60 2,000 1 60 3 { 2d “ 80 4,000 2 120 4 { 3d “ 85 6,000 3 180 5 { 4th “ 103 8,000 4 240 6 { 5th “ 120 10,000 5 300 7 3d Class. 1st plan, 37 2,000 1 60 8