By the exercise of great prudence, it is possible to
attain considerable age withont requiring glasses,
but of a moderate power. Many pereons igno-
rantly, or for the want of a suitable place where
they can purchase, run through the whole assort-
BuiM to regoute mcnt, and finally are forced to use the

their UM, very highest powers. The following
rules may be laid down with regard to this sub-
ject :

Fvrat — ^Young people should never use glasses
with an idea of strengthening their sight

Second. — ^They should be resorted to as soon as
the eyes are distressed in the evening with ordinary
work ; more harm will ensue by abstaining from
Uieir use than by their judicious employment.
7%irA-They should never be used indfscrimi.
nately, nor worn in the open air if it can be
avoided.
Fourth. — ^They should be laid aside when
scratched or broken, and when dimmed, should be
carefully wiped with wash-leather.
Fifth. — As said by another, if people value their
eyesight, they will shun cheap and imperfect spec-
tacles, and puffing opticians.
GLASSBS. 183

Many bny glasses of peddlers, or select them as
they would razor-straps, or penknives,
without regard to the very great im- °"'"=^
portance of their being manufactured with care,
and adapted to the case.
The detailed history of glasses would furnish a
very interesting chapter, but it is foreign to my
present purpose.
This art is no recent invention, though of late it
has attained very great perfection.
. 'tlx* 1 1 History of glasses.
