mechanically perfect._

Interest is a mental yearning. It is the offspring of desire and the
mother of memory.

It goes out spontaneously to anything that can add to the sum of one's
knowledge about the thing desired.

[Sidenote: _The Manufactured Interest_]

A manufactured interest is counterfeit. When a thing is done because it
has to be done, desire dies and "duty" is born. In proportion as a
subject is associated with "duty," it is divorced from interest.

[Sidenote: _Memory Lure of a Desire_]

If you want to impress anything on another man's mind so that he will
remember it, harness it up with the lure of a desire.

Diffused interest is the cause of all unprofitable forgetfulness. Do not
allow your attention to grope vaguely among a number of things. Whatever
you do, make a business of doing it with your whole soul. Turn the
spotlight of your mind upon it, and you will not forget it.

[Illustration: TESTING ABILITY TO OBSERVE, REMEMBER AND REPORT THINGS
SEEN PRIVATE LABORATORY, SOCIETY OF APPLIED PSYCHOLOGY]