CLARK
CLARK
became interested in grinding and polishing re-
flectors for telescopen, and Mr. Clark took up the
work and aided his son in experimenting with
reflectors, which by liis advice they abandoned
at considerable sacrifice and commenced the
manufacture of refracting telescopes. Mr. Clark
discovered in 1853 two new double stars with a
45 -inch glass of his own manufacture. In 1853,
with a glass of 7^ inch aperture, he discovered 95
Ceti and reported his discoveries to the Rev. W.
R. Dawes, the famous double-star observer of
England, who thereupon purchased from him this
glass and afterward four others, including the
8-inch glass, which in the hands of Huggins be-
came well known. In 1859 he was the guest of
Dawes in England where he visited the Green-
wich observatory, attended a meeting of the Royal
astronomical society, and met Sir John Herschel
-and Lord Rosse. He sold one equatorial mount-
ing and two object glasses, one 8, and the other
8| inches, and the results from the use of these
glasses were published by Mr. Dawes in the
monthly reports of the Royal astronomical so-
ciety, giving to the American manufacturer
wide reputation. In 1860 Alvan Clark & Sons es-
tablished themselves at Cambridgeport, Mass.,
and Dr. F. A. P. Barnard ordered for the Univer-
sity of Mississippi a telescope to be larger than
any refractor ever before put in use. The civil war
preventing the delivery of the instrument, it was
sold in Chicago and was afterward in charge of
S. W. Burnham. Among the larger glasses made
by the firm is a 124-inch aperture for the Pritchett
school institute, Glasgow, Mo., and one of the
same size for Dr. Henry Draper of New York
city; one of Hi inches for the Austrian observa-
tory, Vienna; one of 11 inches for the observa-
tory at Lisbon, Portugal; a 12-inch glass for the
Wesleyan universitj-, Middletown, Conn., and a
15i-inch glass for the University of Wisconsin.
In 1871-72 they built the 26-inch clear aperture
telescope for the United States government, for
which they received §46,000; and con.structed one
of equal size for Leander J. McCormick of Chi-
cago, which was presented to the UniA-ersity of
Virginia. He received the degree of A.M. from
Amherst, 1854, Princeton, 1865, Chicago, 1866, and
Harvard, 1874, and was a fellow of the American
academy of arts and sciences. The Proceedings of
the Royal astronomical society gives a list of liis
discoveries made with his own telescopes. He
died in Cambridge, Ma.ss., Aug. 19, 1887.
CLARK, Alvan Graham, lens maker, was born in Fall River, Mass., July 10, 1832; son of Alvan and Maria (Pease) Clark, and descended from Barnabas Clark, one of the earliest settlers of Plymouth colony. He was educated at the jjub- lic schools of Cambridgeport, learned the trade of a machinist and worked with his brother, George
Bassett, in making lenses, becoming a member
of the firm of Alvan Clark & Sons in 1852. He
was a successful observer of astronomical phe-
nomena and discovered fourteen intricate double
stars, among them the companion to Sirius, re-
ceiving in 1862 the Lalande gold medal of the
French imperial academy of sciences. He visited
Europe several times
and was sent by the
United States gov-
ernment to observe
the eclipse of the sun
with Winlock at Shel-
by ville, Ky., in 1869,
and the transit of
Venus at Jarez,
Spain, in 1870, and
with Harkness, the
solar eclipse in Wy-
oming Territory in
1878. In 1882 he com-
pleted a 30-incli ob-
ject glass for the
government of Russia. He was made a fellow
of the American academy of arts and sciences,
of the American association for the advancement
of science, and a member of the Cambridge
and Union clubs. He received a gold medal
from the Russian government for excellence
of telescopic objectives. Among his larger tel-
escopes are the Yerkes refractor, 41i-inch
aperture; Lick observatory, California, 36-inch;
YCRKE5 O05£RVATORY
J^'^^to^ <^<^^
-^--^9,
Pulkova observatory, Russia, 30-inch; Wash-
ington naval observatory, 26-inch; McCor-
mick, University of Virginia, 26-inch; and those
of lesser power at Princeton, Denver, Rochester,
Evanston, Madi.son, and Vienna, ranging from 12
to 24 inches. In May, 1897, he delivered to the
Yerkes observatory. Lake Geneva, Wis., the
lenses for the most powerful telescope in Amer-
ica, which cost the labor of three years with two
assistants, conveying them from Cambridgeport
to Chicago in a special drawing-room car. He
