jurious. Several cases of actual
blindness are recorded as having occurred within a few years from
exposure to concentrated light, and weakness of sight that has unfitted
the individual for usefulness through life has often been thus produced.
The rays of the sun are considered as peculiarly injurious when
reflected from an opposite building or wall, or even when they pass
through a window, and, descending to the floor, are thence reflected to
the eyes. What, then, shall we say of the habit of constructing
school-rooms in such a manner that perhaps a majority of the scholars
are obliged to write and study at desks upon which the direct rays of
the sun shine for a considerable portion of the day unbroken unless it
be by a passing cloud! And yet thousands of school-houses are situated
in such a manner as to create this very necessity all over our country.
At a moderate estimate, the eyes of one hundred thousand children are
taxed in this manner in the schools of the United States every passing
year. A vast amount of discomfort and unhappiness is produced in this
way that might easily be avoided, would parents and teachers take the
trouble. Any exposure of this kind should be immediately obviated,
either by blinds, or by curtains of some soft color. A few newspapers
are much better than nothing. The desks and furniture should be of such
a color that the eye may repose upon them with agreeable sensations.
Nature is clothed with drapery whose color is refreshing to the eye; and
it is false taste, as well as false philosophy, which attempts to dazzle
in order to please it.

_The use of side lights is injurious._ The eye will accommodate itself
to light of different degrees of intensity within a limited range, but
both eyes should be exposed to an equal degree of light. The sympathy
between the eyes is so great, that if the pupil of one eye is dilated by
being kept in the shade, as must, of course, be the case where the light
is on one side, the eye which is exposed can not contract itself
sufficiently for protection, and is almost inevitably injured.

When viewing objects, we should avoid, as far as possible, _all oblique
positions of the eye_. By neglecting this rule, an unnatural and
permanent contraction of the muscle is liable to be produced, as is
illustrated in the numerous instances of strabismus, or cross-eye, which
are every where too common.

_We should accustom the eye to viewing objects at different distances._