Origin and Development of the Morse Code

Source not credited, but quite possibly contemporary with the introduction of telegraphy.
From OTB Vol. 13, No. 3 (December, 1972)

Morse, in the arrangement of his conventional telegraphic alphabet, took as a unit of space or length the shortest available length of line, technically termed a dot. His alphabet was then made up of signs, forty-five in number, formed from three elements: the dot, the space and the dash, arranged in various combinations, representing the following relative values:

Prof. S. F. B. Morse, in considering the mechanical means at command for producing at a distance any permanent mark, perceived that by means of the electromagnet, the motion of a lever, up and down, could be easily and surely commanded; and if a pencil at one extremity of it were made to strike upon a piece of paper. A dot would be made whenever the magnet was charged and quickly discharged. This action, however, without a further device, would
be unavailing to produce variety, since the lever motion is limited to the simple movement of up and down. Hence the idea of moving the paper at a regular rate beneath the pencil.

Thus a dot could be made on the moving ribbon of paper, which, passing onward, the paper was ready to receive (after an interval more or less extended) another dot, or series of dots. Thus, the ability to produce dots in groups at pleasure was demonstrated, and, consequently, groups of dots expressive of various numerals were devised.

In pursuing the experiments with the numerals whose elements were a simple dot and space, it was perceived that, by means of the moving paper, not merely a dot could be produced at pleasure, but if the magnet was kept charged while the paper was in movement, the pencil produced a line long in proportion to the time in which the magnet was charged. This fact introduced a third element for combination, to produce variety in the groups, indicating letters, as well as numerals, to wit: the line or dash; so that dots, spaces and lines in any variety of combination were at command for forming a code of signs. Hence originated what is now universally recognized as the Morse code.

In the arrangement of the alphabet it was desired that no letter should occupy more than five dots, or nine units in length; and none of them, with the single exception of the letter J, exceeds that number. Another principle was specially observed, that of the letters occurring most frequently in the English language, were therefore composed of the fewest and shortest elements. The letter E is thus represented by a single dot; the I and T within the space of two dots or three units, and so on. The numerals were comprised within the value of six dots, or eleven units, to distinguish them more readily from the letters.

Upon the introduction of the Morse system into Germany many years ago, an important arrangement of the alphabet was devised, called the Continental or International Alphabet, and this has been adopted and become universal on all submarine cables as well as land lines, in all parts of the world where the Morse apparatus is used, except in America. It is founded on the Morse, and the only letters that differ from the Morse are c, f, j, l, o, p, q, r, x, y, z; the additional letters peculiar to foreign languages are ä, ö, and ü, é and ñ. The figures are all different, except the figure 4. All these letters and figures are made by dots and lines, the same as the Morse, and only differ in their relative position.

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