vised a mercurial air-pump giving an exhaustion of millionth of an atmosphere, a degree that ha- not been attained by other pumps up to the present time (1898). The methods of photometry that he has originated, and his investigations of phenomena that depend on the physiology of vision, are very ingenious, and he was the first to make quantitative experiments on color-contrast. Although not an artist by profession, he paints in water-colors, is frequently represented at the annual exhibitions, and has been a member of the American water-color society since its foundation in 1866. He was elected to 'the National academy of sciences in 1865, and in 1867 was vice-president of the American association for the advancement of science. The results of his various researches an- included in about sixty memoirs that have appeared in scientific journals, both in the United States and abroad, but chiefly in the "American Journal of Science." Sixteen nf his must important memoirs were originally read before the National academy of sciences, Prof. Rood has published "Modern Chromatics." a work that, besides presenting the fundamental facts as to perception of color, contains the results of numerous original investigations on the subject (New York, 1881).
ROORBACH, Orville Augustus, publisher, b. in Red Hook, Dutchess co.. N. Y.. 20 Jan., 1803; d. in Sehenectady, N. Y., 21 June, 1801. He was
educated in Albany, opened a book-store in Charleston, S. C., about 1826, and was engaged in business there till 1845. During the latter part of that
time he also carried on the book trade in New York city, whither he removed in 1845, and continued in that business till 1855, when he began to
publish and edit the " Booksellers' Medium." He compiled and arranged the ' Bibliotheca Americana," a catalogue of American publications, in-
cluding reprints and original works from 1820 till 1861 (4 vols., New York, 1852-'61).
ROOSA, Daniel Bennett St. John (ro-zah), phy-ifian, b. in Bethel. Sullivan co., N. Y., 4 April, ls:Vs His ancestor, Isaac, was a captain in the
Continental army during the Revolution. Daniel entered Yale in" 1856, but left on account of the failure of his health, subsequently studied chemistry under Dr. John W. Draper in New York city, was graduated at the medical department of the University of New York in 1860, and became resident physician in the New York hospital in 1862. He studied abroad in 1863, devoting himself especially to ophthalmology and otology, and in 1864 settled in practice in New York city. He was professor of the diseases of the eye and ear in the medical department of the University of the city of New York
from 1863 till 1882, occupied the same chair in the University of Vermont in 1875-'80, was a founder of the Manhattan eye and ear hospital, and is now
(.1898) professor of those diseases in the New York post-graduate medical school, of whose faculty he is president. Dr. Roosa is a successful practitioner, eminent as a surgeon, and an acknowledged authority in the branch of his profession to which he has devoted himself, having performed the most difficult and delicate operations that occur in the
prosecution of his specialty. He was president of the International otological society in 1876, and of the New York state medical society in 1879. Yale gave him the honorary degree of A. M. in 1872, and
the University of Vermont that of LL. D. in 1880. He has translated from the German "Troltsch on the Ear" (New York, 1863), and. with Dr. Charles
E. Hackley, "Stellwag on the Eye" (1867); and is the author of " Vest-Pocket Medical Lexicon" (New York, 1865); "Treatise on the Ear," republished in London and translated into German (1806); "A Doctor's Suggestions " (1880); and "On the Necessity of Wearing Glasses" (Detroit. 1887).
ROOSEVELT, Nicholas I., inventor, b. in New
York city, 27 Dec., 1767; d. in Skaneateles, N. Y.,
30 July, 1854. His ancestors were early citizens of
New York. His father, Isaac, was a member of the
New York provincial congress, the legislature, and
the city council, and for many years was president
of the Bank of New York. Nicholas was carefully
educated. His connection with the invention of
vertical steamboat paddle-wheels is described by
John H. B. Latrobe in his “Lost Chapter in the
History of the Steamboat” (Baltimore, Md., 1871). Mr.
Latrobe's investigations show that, soon after the
evacuation of New York by the British, Roosevelt
returned to New York from Esopus, where he then
resided, and where he had made a small wooden
boat, across which was an axle projecting over the
sides with paddles at the ends, made to revolve by a
tight cord wound around its middle by the reaction
of hickory and whalebone springs. In New York
he engaged in manufacturing and inventing in that
city, subsequently became interested in the Schuyler
copper-mines in New Jersey on the Passaic
river, and from a model of Josiah Hornblower's
atmospheric machine completed a similar one, built
engines for various purposes, and constructed those
for the water-works of Philadelphia. He was also
at the same time under contract to erect rolling-works
and supply the government with copper
drawn and rolled for six 74-gun ships. In 1797,
with Robert R. Livingston and John Stevens, he
agreed to build a boat on joint account, for which
the engines were to be constructed by Roosevelt,
and the propelling agency was to be that planned
by Livingston. This experiment failed, the speed
attained being only equivalent to about three miles
an hour in still water. On 6 Sept., 1798, Roosevelt
had fully described to Livingston a vertical
wheel, which he earnestly recommended. This is
the first practical suggestion of the combination
that made steam navigation a commercial success,
although four years later Robert Fulton believed
that chains and floats were alone to be relied on.
Livingston, however, had replied to Roosevelt's
proposition on 28 Oct., 1798, that “vertical wheels
are out of the question.” But in the spring of 1802,
Livingston having communicated Roosevelt's plan
to Fulton, they adopted the former's view, and in
January of the next year launched a boat that was
propelled by Roosevelt's vertical wheels. Roosevelt
in the mean time became greatly embarrassed
financially, the government failed to fulfil its
contract with him, and he was unable to put his plans
in operation. In 1809 he associated himself with
Fulton in the introduction of steamboats on the
western waters, and in 1811 he built and navigated
the “New Orleans,” the pioneer boat that descended
the Ohio and Mississippi rivers from Pittsburg
to New Orleans in fourteen days, he having
previously descended both rivers in a flat-boat to
obtain information. In January, 1815, he applied to
the legislature of New Jersey for protection as the
inventor of vertical wheels, for which he had
obtained letters-patent from the United States in
December, 1814. The legislature, after discussion,
decided that “it was inexpedient to make any special
provision in connection with the matter in controversy
before the body,” and there the matter rested.
Roosevelt's papers came into the possession of
Richard S. Cox, his executor, from whom they were
obtained in 1828, and from these, with others from
the papers of Chancellor Livingston, a case was
prepared and submitted to Roger B. Taney, which
