nce 1885 has been professor of Physics at
Wuerzburg; his discovery of the X-rays was made in 1898, and has won him a
wide celebrity; _b_. 1845.

ROeNTGEN RAYS, described by Dr. Knott as "rays of light that pass
with ease through many substances that are optically opaque, but are
absorbed by others." "For example," he says, "the bony structures of the
body are much less transparent than the fleshy parts; hence by placing
the hand between a fluorescent screen and the source of these rays we see
the shadow of the skeleton of the hand with a much fainter shadow of the
flesh and skin bordering it." See Dr. Knott's "Physics."

ROOKE, SIR GEORGE, British admiral, born at Canterbury;
distinguished himself at the battle of Cape La Hogue in 1692; in an
expedition against Cadiz destroyed the Plate-fleet in the harbour of Vigo
in 1702; assisted in the capture of Gibraltar from the Spaniards in 1704,
and fought a battle which lasted a whole day with a superior French force
off Malaga the same year (1650-1709).

ROON, COUNT VON, Prussian general, born in Pomerania; was Minister
of War in 1859 and of Marine in 1861; was distinguished for the important
reforms he effected in the organisation of the Prussian army, conspicuous
in the campaigns of 1866 and 1871-72 (1803-1879).

ROOT, GEORGE FREDERICK, a popular American song-writer, born at
Sheffield, Massachusetts; was for some time a music teacher in Boston and
New York; took to song writing, and during the Civil War leaped into fame
as the composer of "Tramp, tramp, tramp the Boys are Marching," "Just
before the Battle, Mother," "The Battle Cry of Freedom," and other
songs; was made a Musical Doctor by Chicago University in 1872
(1820-1895).

ROOT AND BRANCH MEN, name of a party in the Commons who in 1641
supported a petition for the abolition of Episcopacy in England, and even
carried a bill through two readings, to be finally thrown out.

ROPEMAKER, THE BEAUTIFUL. See LABE, LOUISE.

RORKE'S DRIFT, a station on the Tugela River, Zululand, the defence
of which was on the night of the 24th January 1879 successfully
maintained by 80 men of the 24th Regiment against 4000 Zulu warriors.

ROSA, CARL, father of English opera, born at Hamburg; introduced on
the English stage the standard Italian, French, and German operas with an
English text (1842-1889).

ROSA, SALVATOR, Italian painter, born near Naples, a man of
versatile ability; could write verse and compose m