The Portland daily press., 1883-05-10

OF spectacles with transparent glasses Is
sometimes used when the wearer wishes to
avoid the necessity OF carrying two pairs of
glasses. In such cases the second pair are
attached to frame by hinge. The single
pair are used for reading, and when the side
glasses are put down over the others double
power is obtained and the glasses are made
lit for street use.
Pebbles were supposed until recently TO
nave been comparatively new material for
use in spectacle lenses. This is not the fact,
however, for there can now be seen in a
Broadway store pair of spectaeles of nn-
Known age which came from China. The
lenses are pebble according TO all the tests
used in determining pebble. The common
test used is the tourmaine test. bit of
tourmalne is mounted in circular frame.
Between two such frames the glass to be
tested is placed. If the tense is of glass 1t
viii appear perfectly opaque when held up
to the light. If of pebble, faint yellowish
light will show through, the pebble being so
much more transparent than glass as to per-
nit the passage of the "a of light through
tourmalne and pebble
The ordinary form of the lens Is of course
oval, but circular, octagonal, and even square
lenses are lifted to frames to satisfy the ca
price OF the wearer. The elongated octagon
is the commonest of the peculiar forms of
glasses, and this is nearly always the shape
OF the glasses in lorgnettes The coqaette
is French shape, which is vulgarly known
as ''the scoops The lens is made In an all
most hemispherical shape, and the advan-
tages claimed for it are that it fits the eye
more closely and also protects 1t. The lens
is clumsy looking affair and win therefore
never become popular in this country. Peo-
pie who travel much or who are employed
ON railroads and wish to protect their eyes
from flying cinders prefer to use the common
form Of lens, to which is attached frame
with network of very fine wire, which fits
closely to the face completely protecting both
the eye and the lid A somewhat common
form of spectacles used nova days is one
with glasses of two different powers COM
bined in the same lens. These are known
as blfocal lenses. The upper half of this
lens Is OF greater power than the lower. The
object of the double lens is to enable per-
son to use the lower half while reading or
writing and the upper half to see at dis
lance. Such glasses are used to consider
able extent by ministers and other public
speakers who speak from manuscript, and
they are sometimes used by artists while
sketching In the latter case the artist sees
the object he is skeiching through the upper
half of the glass and does the transferring to
paper while looking through the lower half
Another peculiar form of lens is the half
oval. This has come to be known as the
"pulpit-eye" shape because it is largely used
by ministers. They can read their sermon
through the glasses, and look oyer the top of
them when looking at the congregation.
There has been within the past few years,
a complete change in the form of spectacle
frames. The old hinged frames, with pieces
dropping back of the ears to hold the glasses
in place have been abandoned, and the pop
n form 10 hat xu1 hos L.. -