or otherwise, and lo!
when you least expect it, it will pop into your thoughts.

If your memory is good in most respects, but poor in a particular line,
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

"To briefly show its use, suppose it is desired to fix 1,142 feet in a
second as the velocity of sound, t, t, r, n, are the letters and order
required. Fill up with vowels forming a phrase like 'tight run' and
connect it by some such flight of the imagination as that if a man tried
to keep up with the velocity of sound, he would have a 'tight run.'"

[Sidenote: _Scientific Pedagogy_]

The same principle is at the basis of all efficient pedagogy. The
competent teacher endeavors by some association of ideas to link every
new fact with those facts which the pupil already has acquired.

In the pursuit of this method the teacher will "compare all that is far
off and foreign to something that is near home, making the unknown plain
by the example of the known, and connecting all the instruction with the
personal experience of the pupil--if the teacher is to explain the
distance of the sun from the earth, let him ask, 'If anyone there in the
sun fired off a cannon straight at you, what should you do?' 'Get out of
the way,' would be the answer. 'No need of that,' the teacher might
reply; 'you