The Toledo chronicle. [volume] (Toledo, Tama County, Iowa) 1873-1924, 1876-12-21

~ ktsVfSVSS't,s
We are indebted to the late Sir Charles
Whcatstone for series of Investigations
on binocular vision, which finally cu-
minated in the invention of that now very
popular little apparatus, the stcreoscopc.
1t was in 1928 hat Whcatstone called at
tcntion to Il fact until then hardly noticed
namely, that the PERCEPTION of relief in
objects is the result of the superposition
OF The images, one on each eye; but these
images slightly differ from each other
The mind, guided by the experience Of
MANY Yeas, receives in this way the im-
preston of various distances; and Wheat
stone discovered that this impression
may also be given to the mind by two
pictures if each is drawn so rs to cores
pond, respectively, to the image received
by each eye In order to prove this.
Wheatstone invented the stereoscope
Considered from the standpoint OF pure
Science (apart from its practical applica-
ton for amusement, instruction, and re-
search, and the biuocular microscopes
and telescopes that have grown out OF
iO this discovery of Wheatstone's is per-
haps as interesting as any othcrinveniion
of recent date, not excepting the ka-
leidoscopc, the telephone, the pseudo
scope, and the revolving mirror for meas
uring the velocity of light, etc. Sir David
Brewster, who was enormously supposed
BY many to have invented the stereoscope
used often, while insisting on the import
ance of this new conquest in physical
science. to describe this instrument I'M
hcsitatingly as the most remarkable gilt
with which the study of binocular VISION
had been enriched.
The first sttreoscope by which Wheat
stone demonstrated his discovery was Il
rejecting stcrcoscope. Two vertical mir
rors were placed so as to make, respect
lively, an rnglc of Is min. with the axes OF
the ewes, and in such a position as to re-
feet the rays coming from the right and
left into the eyes, the mirrors being join
ed at middle point between the axes.
Two perspective drawings, correctly
made SO as to correspond with the image
which the real object would make in
each eve, were then so placed at the
right and left, as to cause these images in
the mirrors to coincide in the act OF Wis
ion, and the illusion was perfect. Wheat
stone found later that he could dispense
with the mirror and simplify the appara-
tus by using two prisms, to.which he had
lenses attached so as to magnify the
drawings. Brewster finally had prismat-
ic lenses made, joined by their thinest
edges, by which small drawings, placed
at the distance of, say, three inches,
could be made to coincide for the vision,
1t should, however, be mentioned that
Duboscq, of Paris, was the first to give to
the stcreoscope the simple practical form
in which it is now seen in the trade; but
its popularity did not become established
until photography came to its aid, to
make bnocular pictures perfect in all
their details.
1t was at the first. universal expo siton
in London, 10 1851, that Doboscq exhibit
ed stercoscopc, and then for the first
time the instrument became noticed by
the public, although it had been know
to scientists for 10 years, during which
time DR.. Carpenter an | others had con
tinually, in lectures on physical sciences,
exhibited the instrument and demonstra-
ted the principles of Wheatstone's dlscov-
cry According to the statements OF one
manufacturer of optical instruments, a
long time elapsed before the people be-
gan to appreciate the beauties of the ster-
eoscope; and for several years no sales
of any Importance could be made. But
at last its merits were realized, and sud
denly large demand sprung up. The
stcrcoscope soon became IL fashion; and
the manufacture of the different forms OF
the Instrument Tvs rying in price from %
cents to $l00) the grin ling of the prlS
matte lonsos, and tho production of the
Photographic pictures ION paper and on
rlass) have now become an important
branch of business, in which thousands
of artists and workmen are occupied.
One of the most extensive Western
manufacturers of Stereoscopic Views Is
Mr.. w. G. Chamberlain, Denver City,
Colorado. 1t is well known that thu
scenery of the Rocky Mountains is not
excelled in the world for grandeur and
beauty and Mr.. Chamberlain has succeed
ed in getting some of the finest views we
have seen. His views are highly finish
ed, and include not only mountain seen
cry, but cities, towns, NC, throughout
the West. Any of Our readers who wish
to enjoy the beauties of Mountain seen
cry, without the expense or trouble OF
visiting it, cannot do bette than order
some views of Mr. Chamberlain. He
will SIND catalogue to any address.