Astronomer; born in
Roxboro, Pa., April 8, 1732; was of German descent.
His great-grandfather established at
Germantown, in 1690, the first paper-mill in
America.
Accidentally falling in with instruments and mathematical books of a deceased uncle while working on his father's farm, David had mastered
Newton's
Principia and independently discovered the methods of fluxions before he was nineteen years of age. He early became a skilful mechanic, and, at the age of twenty-three, planned and constructed an orrery, which was purchased by Princeton College.
He afterwards constructed a larger and more perfect one for the
University of
Pennsylvania.
In 1763 he was employed in determining the
Mason and Dixon's line (q. v.), and afterwards fixed other State boundaries.
In 1769 the
American Philo-
[
442]
sophical Society appointed him to observe the transit of
Venus at
Philadelphia.
He erected a temporary observatory for the purpose on the
Walnut Street front of the State-house.
It is said that the emotion of
Rittenhouse was so great at the apparent contact at the time of the transit that he fainted.
In Philadelphia Rittenhouse continued his manufacture of clocks and
mathematical instruments several years.
From 1777 to 1779 he was treasurer of
Pennsylvania; in 1791 he succeeded
Franklin as president of the American Philosophical Society; and from 1792 to 1795 was director of the United States Mint.
He was a member of the Academy of Arts and Sciences of
Boston.
He died in
Philadelphia, June 26, 1796.
