it is because you do not interest yourself in that line, and therefore
have no material for association. Blind Tom's memory was a blank on most
subjects, but he was a walking encyclopedia on music.

[Sidenote: _Basic Principle of Thought-Reproduction_]

_To improve your memory you must increase the number and variety of your
mental associations._

Many ingenious methods, scientifically correct, have been devised to aid
in the remembering of particular facts. These methods are based wholly
on the principle that _that is most easily recalled which is associated
in our minds with the most complex and elaborate groupings of related
ideas_.

[Sidenote: _Methods of Pick_]

Thus, Pick, in "Memory and Its Doctors," among other devices, presents a
well-known "figure-alphabet" as of aid in remembering numbers. Each
figure of the Arabic notation is represented by one or more letters, and
the number to be recalled is translated into such letters as can best be
arranged into a catch word or phrase. To quote: "The most common
figure-alphabet is this:

1 2 3 4 5 6 7 8 9 0

t n m r l sh g f b s
d j k v p o
ch c
g qu z