Springfield globe-republic. (Springfield, Ohio) 1884-1887, 1885-02-23
STONE TO pEEK THHC'.
An Opticians Views on Spectacles-Good
Glass Given the Preference.

A" Opticians Views on specta"les-Good
''S '''tn ."o i''e' '"'''
There is a GOOD story told on down.
town optician. He sold pair of gold
trimmed spcctacles. PROTESTING that the
sights were pebbles and not GLASS. The
purchaser later on had the ALLEGED peb-
bles taken out by another optician and
fitted into eyeglasses. The latter were
taken to the first optician. who was
asked whether the siG5hts were pebbles
or glass. He rrcopnized immediately
the mark of his connection on the
frame, and unhesitatingly pronounced
to be glass what he had sold as peb-
bles. adding that the only genuine arti-
Gle could always be found at his shop.
People who wear spectacles or eve
glasses, either from necessity or foolish
ness-and tbcre is no small number of
the latter sort-are as a rule predis-
posed in favor of pehbles. They have
been told that pebbles are clearer than
GLASS. that they are more cooling to the
ewes and that they are more durable
As a matter of fact. the only ADVANTAGE
pebbIes baye-to the dealer.is that thev
cost more money; there is consequently
more money in handling them. Inas-
much as there is quite a number of peo-
ple who believe that A ncw-fangled arti-
Gle with a HIGH price attached is better
than an old-fasbioned one at reasonable
rates nehbIas will have their RIM. espe-
ciallv with that class of people who
wear glasses because they think it will
make foolish features look wise.
II
subject of pebbles and glasses the Her
aid reporter sought out a Randolph
street firm of opticians whose members,
tbouob younc. have an excellent repu-
tation in their line.
..Judoe for yourseIf " replied the gen
tIeman who was interviewed in regard
to the difference between pebbles and
glasses. with special reference to the
marks by which these differences can
be detected even by the uninitiated. A
fine steel file was produced, and upon
its furrowed surface glass sight and a
pebble sight were rubbed alongside of
each other. The mark made by the
glass was line of fine. grayish-white
dust. while the mark made bv the peb-
BILE had simply polished the metal with
out leaving any deposit.
THAT is the simplest method" said
the optician; ..one that ANYBODY can
apply. The pebble. being a stone, is
harder than glass. which is compound.
A more scientific test-for under GER
tain conditions glass as hard as pebble
can be produced-is what we call re-re-
Election. A tester containing two
prisms, between which the glass to be
tested is placed. will be n0n-transpar-
ent. while. when pebble is placed be-
tween the prisms. the latter will permit
semi-tranSparency. This, however, is
but an optical delusion. for the light
does not tpenetrate.through both prisms
and the pebble. but through the sides of
the latter and through the prism next
TO the eve. This demonstrates that in
spectacies and eyeglasses with pebbles
as sights the ravs of light which should
pass through the optical lens alone are
also reflected bv the grain formation of
the pebble, thus producing re-retiection,
which is hurtful to the eyes. In some
cases re-reflection is necessary so that
the artificial light is nearly as possible
the same as the natural. but these cases
are exceedingly rare. To be palmer to
the popular understanding: If the lenses
of an Opera-glass would be pebbles in
stead of glass the objects seen would be
to the ordinary eye clothed in all the
colors of the rainbow" No profess