essential for the manufacture of a good grating is the manufacture and adjustment of a perfect screw. The reader who desires to learn how such a screw is made should consult Professor Rowland's article on the screw in the Encyc. Britannica. For a thorough discussion of the diffraction-grating see Preston's Theory of Light, Chap. 9.
Diges′tion in plants is essentially the same process as in animals. It consists in producing such chemical changes in insoluble foods that they become soluble in water, and consequently fit for absorption or transfer; or, when already soluble, in reducing them to simpler forms. There are no special digestive organs in plants comparable to the alimentary canal of animals, with its connected glands; and likening the leaves to the stomach is misleading. Digestion is usually accomplished by the action of enzymes (which see) or ferments secreted by the living protoplasm. (See Secretion.) In some cases these enzymes are produced in special glands; in others they are formed by the same cells that have other functions. Digestion often occurs outside the plant-body as when the embryo secretes diastase (see Enzymes) to digest the starch stored around it; or when a fungus digests the cellulose of a cell-wall which it is penetrating. Or digestion may occur within the plant-body, as when the starch stored in a potato-tuber is digested in order to be transferred to the growing regions, or the starch-granules formed in a leaf are digested to be carried away to places of use or storage.
Dijon (dē̇′zhôn′), the former capital of the old duchy of Burgundy and the chief city of the French department of Côte-d' Or, is situated on a plain at the foot of Mt. Afrique, 1,916 feet in height. It is an important place as a part of the inner line of French defenses, and the neighboring hills are crowned with strong forts. It is a well-built town, with broad streets and open squares, boulevards and beautiful surroundings. The Gothic cathedral, which dates from the 13th century, has a spire 301 feet high. Dijon, known to the Romans as Dibio, passed in the 5th century from Burgundy to France. In the 9th century it was ruled by its own counts. In 1007 it was united to the duchy of Burgundy and made its capital. It became French territory in 1479. It yielded to a German army in 1870. Population, 76,847.
Dike. See Jetty.
Dilke (dĭlk), Rt. Hon. Sir Charles
Wentworth, an English statesman and
author, was born at Chelsea, Sept. 4, 1843.
He graduated at Cambridge, and was soon
after called to the bar. He published in
1868 a description of his travels in the United
States, Australia and New Zealand under
the title, Greater Britain. He was elected to
Parliament in 1868, was under-secretary for
foreign affairs and also president of the
SIR CHARLES DILKE
local-government
board under
Gladstone. In
1886 his connection
with a
divorce case
prevented his reëlection
to Parliament,
but his
influence was still
felt through his
writings. His
essays, collected
under the title
of The Present
Position of European
Politics,
were first
published in the
Fortnightly Review.
He has also
published works on the British army,
army-reform, imperial defense and the British
empire and a work entitled Problems of
Greater Britain. In 1892 he was again
returned to Parliament.
Dillon, John, Irish Nationalist member
of Parliament and leader of what is known
JOHN DILLON, M. P.
as the Plan of
Campaign, was
born at Dublin in
1851, and entered
the British Parliament
in 1880 as
member for
Tipperary and since
1885 has sat for
East Mayo. He
has suffered
imprisonment twice
(in 1881 and in
1891) for treasonable
offenses. He
at one time was a
close ally of
Parnell, and later
actively opposed
him. He succeeded Mr. Justin McCarthy
in 1896 as leader of the Nationalists, and
is known “for his intense religious fervor
and his transparent sincerity,” though
neither political party in the House of
Commons has cared to endorse his attitude
as an Irish agitator.
Dinwid′die, Robert, governor of Virginia from 1752 to 1758, was born in Scotland about 1690. His rule as governor was not successful, his ill-temper and avarice making him very disagreeable to his subjects. He was the first to suggest the taxing of the colonies to the British board of trade. He discerned Washington's military ability, and made him adjutant-general of one of the four military districts of Virginia. He died in England in 1770.
