_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
We find by comparison that Morse’s plan, No. 3, of using a single wire, with a single instrument, produces 60 characters per minute; while No. 1, with 13 wires, and one instrument, produces 480 characters per minute. Let, however, the 13 wires be multiplied by 60, (the number of characters which a single instrument of the plan, No. 3, can transmit,) the number of characters which 13 wires, with 13 instruments would then produce, are 780 or 300 more than the _single instrument_, with 13 _wires_. The same comparisons may be made with the other plans, and it will be found that no advantage can be gained by their adoption.