Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1892-03-17
AMERICAN INGENUITY
Once More Scores q Signal Triumph
in an Important Field.
OPTICAL GLASS MANUFACTURED
At the New Indiana Plant Of q Well-KnowI
Pittsburg Firm.
THOROUGH TESTS MADE BY BRASHEAR

Optical glass for the making Of telescope
lenses, prisms and photographs cameras has
been made at Elwood, Ind, by George A.
Macbeth & Co., of this city. 1t is stated
by Mr.. F. NJ Gessner that sufficient has
been accomplished to demonstrate beyond
doubt that this country will no longer be
forced to depend upon Europe for a supply
of optical glass
The optical glass department has been in
operation during several weeks, and it Is
said the manufacture has passed the expert
mental stage. Several alterations Of the
furnace were required before it could be got
to work properly, but several pots of glass
have been made and number of pieces
polished and rigidly tested by John A.
Brashear, Of Allegheny, and pronounced
absolutely perfect, and as Mr.. Brashear in
his business of many years has used the
glass of all foreign manufacturers his
opinion is accepted as final.
Some Fine Work on Hand.
At MI. Brashear's workshop a prism is
being made for Prof Nicholson, Clark Uni
versity, Worcester, Mass, 24x3H inches.
and second in the rough, but with the
ends. polished and found perfect, is being
made for Prof. Langley, of the Smithsonian
Institute, Washington. This is 5x6 inches,
one of the largest in the world. Mr. Bra
shear has had .20-inch lens cast, and he
will polish and finish it for exhibition at
the Columbian Exposition in Chicago next
year. Scientific men all over the country
have been absorbingly interested in the ex-
periments, as they have heretofore been
compelled to depend on foreign glass
makers for lenses and prisms.
There are less than half dozen factories
in the world making optical glass. They
are in Munich, Jena, Paris and
Birmingham. The manufacture has been
closely guarded. In Neufchatel, in 1745, q
Swiss named Guinand was born, and he be-
came matchmaker. He attempted to
make telescope and succeeded, and being
that by stirring the melt in the pot for Is to
20 minutes at stated intervals, he secured a
perfectly homogeneous glass, overcoming
the tendency of the lead used to settle to
the bottom and producing spots and stratif-
cations differing in density and attractive
power.
A Big Step in Advance.
Edward Fell, who superintended the
making of this glass at Elwood, is q great
grandson of Guinsnd, the Swiss watch
maker, and under Mr.. Feils direction the
lens used at the Lick Observatory, Califcr-
mia, was cast in 1882. He is the son of
Fell, of the firm of Fell, Pere & Mantois,
Paris
This country has many skillful makers of
scientific instruments, and much of their
work has found a market among European
scientists, but our makers have hitherto
been compelled to first import lenses and
prisms. bringing them from the countries
to which they were subsequently, returned.
The industry is rather extensive one, as
scarce any boy or girl feels content now
unless they possess Kodak and an
opera glass, while in hilly countries no res
idence is complete unless furnished with q
field glass. ..