Ellis, in his _Voyage to Hudson's Bay_, written in the middle of last
century, says of the Esquimaux:--"Their snow eyes, as they very properly
call them, are a proof of their sagacity. They are little pieces of wood
or ivory, properly formed to cover the organs of vision, and tied on
behind the head. They have two slits, of the exact length of the eyes,
but very narrow; and they see through them very distinctly, and without
the least inconvenience. This invention preserves them from
snow-blindness, a very dangerous and powerful malady, caused by the
action of the light strongly reflected from the snow, especially in the
spring, when the sun is considerably elevated above the horizon. The use
of these eyes considerably strengthens the sight, and the Esquimaux are
so accustomed to them, that when they have a mind to view distant
objects, they commonly use them instead of spy-glasses."
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