word, to which, on the motor side, corresponds the system of delicately
adjusted movements which result in the writing or typewriting or other
graphic method of recording speech. The significant feature for our
recognition in these new types of symbolism, apart from the fact that
they are no longer a by-product of normal speech itself, is that each
element (letter or written word) in the system corresponds to a specific
element (sound or sound-group or spoken word) in the primary system.
Written language is thus a point-to-point equivalence, to borrow a
mathematical phrase, to its spoken counterpart. The written forms are
secondary symbols of the spoken ones--symbols of symbols--yet so close
is the correspondence that they may, not only in theory but in the
actual practice of certain eye-readers and, possibly, in certain types
of thinking, be entirely substituted for the spoken ones. Yet the
auditory-motor associations are probably always latent at the least,
that is, they are unconsciously brought into play. Even those who read
and think without the slightest use of sound imagery are, at last
analysis, dependent on it. They are merely handling the circulating
medium, the money, of visual symbols as a convenient substitute for the
economic goods and services of the fundamental auditory symbols.

The possibilities of linguistic transfer are practically unlimited. A
familiar example is the Morse telegraph code, in which the letters of
written speech are represented by a conventionally fixed sequence of
longer or shorter ticks. Here the transfer takes place from the written
word rather than directly from the sounds of spoken speech. The letter
of the telegraph code is thus a symbol of a symbol of a symbol. It does
not, of course, in the least follow that the skilled operator, in order
to arrive at an understanding of a telegraphic message, needs to
transpose the individual sequence of ticks into a visual image of the
word before he experiences its normal auditory image. The precise method