As a model, we give the nine expressions of the eye in the subjoined chart.

[Nine expressions of the eye]

For ordinary purposes it is sufficient to understand the nine primary expressions. There are many others which we merely indicate. In sleep there may be an inclination either way. The top of the eyebrow may be lifted.

Thus in the concentric state, three types may be noted, and these go to make twenty-seven primary movements. The lower eyelid may be contracted; the twenty-seven first movements may be examined with this, which makes 2×27.

A movement of the cheek may contract the eye in an opposite direction, and this contraction may be total, which makes eighty-one expressions belonging to the normal glance alone.

This direct glance may also be direct on the inferior plane, which makes 2×81; for these are distinct expressions which cannot be confounded.

This movement could again be an upward one, which would make 3×81.

The movement may be outward and superior, or it may be simply outward; it may also be outward and inferior. A special sense is attached to each of these movements,--a sense which cannot be confounded with any of the preceding movements.

By making the same computation for the three glances above noted, we shall have from eight to nine hundred movements.

All this may appear complicated, but with the key of the primary movements, nothing can be more simple than this deduction.