Charles A. Spencer's Trunnion Model Microscope c. 1855
From Carpenter's The
Microscope and its Revelations, first American
edition, 1855.
Mr. Charles A. Spencer of
Canastota, New York, has manufactured a microscope of
great excellence, the objectives of which will bear
comparison with the best of foreign construction. His
common angle of aperture for 1/4 inch objectives is 135
degrees; for 1/8 inch, 170 degress, and for 1/12 and
1/16 inch, 176 degrees. This. is believed to be the
largest angle ever given to an object-glass, and for
sharpness of definition and power of penetration, they
are unexcelled by any of foreign make.
To Mr. Spencer is due the
credit of having first resolved, with lenses of his own
construction, the fine markings on the Navicular
Spencerii and Grammatophora Subtilissima: these minute
shells have since been adopted by microscopists as
test-objects for the highest powers. The Navicula
Spencerii, will exhibit one set of lines with Mr.
Spencer's 1/4 th-inch object-glass: both sets with the
1/8 th-inch. The Glrammatophora Subtilissima is a good
test for a 1/12 th or 1/16 th.
Of several microscopes
made by Mr. Spencer, two or three only will be here
noticed. His first-class or best instrument is mounted
on trunnions, and embraces all the acknowledged
improvements, in form and stage, whereby the greatest
steadiness and freedom from tremor are secured. The
price of this instrument with all the accessories and a
full set of object-glasses will approach $350 (Fig,
426)
The following was
extracted from The National Cyclopedia of American
Biography, vol. XIII, 1906.
SPENCER, Charles
Achilles,
lensmaker, was born at Lenox, Madison co., N. Y., Sept.
13, 1813, son of Gen. Ichabod Smith and Mary (Pierson)
Spencer, and a descendant of Thomas Spencer, the first
of the family in America. The line is traced through
Thomas's son Thomas, through his son Samuel, his son
Thomas, his son Eliphalet, and his son Eliphalet, the
father of Ichabod Smith Spencer. The last named was an
officer in the war of 1812. The son was educated at
Cazenovia Academy, Hobart College, and Hamilton
College. He displayed his natural aptitude at a very
early age, making his own optical glass when only
twelve years old. In 1838 he announced himself as a
manufacturer of telescopes and microscopes, locating
his workshop at Canastota, N. Y., and here, in spite of
busmess reversals he continued to devote himself to the
perfection of the achromatic telescope and microscope,
later becoming the pioneer in developing the
possibilities of lensmakmg as applied to the
microscope. Ten years later (1848) there issued from
this little shop at Canastota lenses that mystified
both English and French microscopists, chiefly because
of their great resolving power. He had succeeded in
making the microscope objectives so effective as to
accomplish results in " definition " before unknown,
surpassing the efforts of the best European opticians
and upsetting their claim that they had obtained the
largest angular pencil of light that could be passed
through a microscope object glass. He had proved by
actual construction that the angle of aperture in these
higher power objectives could be greatly increased, and
with it their defining and resolving powers. The
English makers charged Mr. Spencer with the I knowledge
of some mode of working glass as yet unknown to other
opticians, and while this was partly true, his chief
success was due to his tact in figuring the lenses so
as to balance the aberrations, a process so delicate
that it would have availed no one not possessed of the
same skill to copy curves. From this time forward Mr.
Spencer kept steadily in advance of foreign opticians
as to angle of aperture; and his microscopical
objectives were pronounced the best in the world. In
the fall of 1873 a disastrous fire broke out in
Canastota, destroying his shop with nearly all his
tools and machinery (the accumulation of many years),
together with a large amount of finished and unfinished
work. Crippled, but not disheartened, he continued his
work under difficulties, and in 1875 entered the employ
of the Geneva Optical Works, Geneva, N. Y., where he
worked for two years. During 1854-56 his business was
conducted under the firm name of Spencer & Eaton,
his partner being A. K. Eaton, and in 1877 he started
the firm of C. A. Spencer & Sons, with his sons
Herbert R. and Clarence Leslie Spencer, and Major O. T.
May, his son-in-law. This association lasted for three
years, when the health of Mr. Spencer, Sr., failed to
such an extent that he gave up active work. On Aug. 10,
1881, Charles A. Spencer was elected one of the first
honorary members of the American Society of
Microscopists. He was married July 10, 1838, to Mary
Morris, daughter of Lonson and Hannah Stilwell, of
Manlius, N. Y., and had six children. He died at
Geneva, N. Y., Sept. 28, 1881.
For an
additionaL discussion of the life and work of
Charles A. Spencer (1813-1881), America's first
microscope maker, see Three American Microscope
Builders published by the American
Optical Company 1945.
The microscope shown on
this page, while unsigned, is an example of Spencer's
Trunnion microscope. When originally found, this
important and rare American microscope had been
converted to a lamp. The lamp components have now been
removed and the microscope has been restored. The
mirror, condenser optics, and slide carrier are
replacements.
