SEYMOUR
1731
SHADOW
islands are under an executive council, with an administrator who has the rank of Governor. The capital is Victoria on Marie" Island, which has a good harbor and has lately been made a coaling-station. Communication with the islands is had by the steamers of the Messageries Maritimes, •which ply once a month (carrying the mails) between Marseilles and Mauritius, and occasionally by the steamers of the British India Steam Navigation Company. The islands have had telegraphic communication with Mauritius and with Europe since 1893. There are good schools on the islands, with good roads on the chief islands, as Marie", Praslin and La Digue. The imports from the Seychelles into Great Britain (chiefly of drugs) amount in value to about $150,000: the exports consist of vanilla, cocoanut-oil, soap, guano, salt-fish, tortoise-shell, coffee and cocoa. Consult Salmon's Crown-Colonies of Great Britain and Belcher's Account of the Seychelles,
Sey'mour, Hora'tio, was born at Pompey, N. Y., May 31, 1810. He studied at a military school and became a lawyer. In 1841 he entered the New York assembly as a Democrat, and was three times re-elected, in 1845 being chosen speaker. Defeated for governor in 1850, he was elected by a large majority two years later. Seymour came into great prominence as one of New York's war-governors, holding this office during the draft-riots in New York City. He presided over the Democratic national convention of 1868, which was held in New-York City. He had refused to be a candidate, but on the 226. ballot was nominated for the presidency by a sudden wave of enthusiasm, in spite of his loudly spoken
frotestations. He, however, received but o electoral votes. He died at Utica, N. Y., Feb. 12, 1886.
Sforza (sfor'tsd), Frances'co, when 23 succeeded his father, Muzio Attendolo, the founder of the family, who was called Sforza, meaning "stormer" (of cities), in command of a famous band of condottiere, soldiers who sold their swords to the highest bidder. He fought at times for and against the pope, Milan, Venice, and Florence. He invented a better system of tactics than had been in use, and it soon came to be taken for granted that victory was certain for the party which had his support. So it came about naturally that the peasant chief won the hand of Bianca, the only child of the duke of Milan. Meanwhile Sforza wrested Ancona and Pesaro from the pope. At the death of his father-in-law in 1450, he gained the dukedom by a combination of stratagem and force. He made firm his authority over all Lombardy and several districts south of the Po, gained the favor of Louis XI, who gave him Savona and Genoa, and won the love of all his subjects. Though himself ignorant, he loved
and protected letters. Sforza died on March 8, 1466, and was followed by five dukes of his family.
Shady an important food-fish belonging to the herring family. The American shad is more valued than the European species. It ranges along the Atlantic coast from New England to the Gulf of Mexico, and ascends different rivers to spawn. This species has been successfully introduced on the Pacific coast. The full-grown fish is about 30 inches long. Its color is bluish, with silvery sides and usually a dark blotch behind the gill-covers and, often, several in a row behind this. These fish were among the first to be protected and artificially propagated by the United States Fish Commission. The result of this care was to increase their numbers greatly. Statistics show that the catch of shad in 1890 was two and one half times that of 1880.
Shad'dock, a native tree of the East Indies, which has been long grown in southern Europe. Its name is said to come from Captain Shaddock, who introduced it into the West Indies in 1810. It has large, white flowers, and its fruit also is very large, sometimes weighing from 10 to 14 pounds, roundish and pale yellow. The pulp is green and watery, ana has a slight acid taste. Finer and smaller than the shaddock proper is the pomelo (also called pummelo, pompemioose and grapefruit), a variety rather larger than an orange, which bears its fruit in clusters. Both kinds are grown in Florida and sold in the north.
Shad'ow, in optics the region immediately behind an opaque object which cannot be illuminated by a source of light in front of the opaque object. If the source of light is a single point, we find that the shadow is geometrically similar to the outline of the opaque object, which is a consequence of the fact that light moves in straight lines in a homogenous medium. Such a shadow is exhibited in Fig. i. In case the luminous source is not a single point, but an extended body, we find that the shadow consists of two parts, one a
FIG. I
central, dark area, called the umbra, the other a partly illuminated border, called the penumbra. This is well-illustrated in the case of the sun and earth shown in Fig. a. The penumbra, as will be evident from the figure, is merely that region which is illuminated by some but not all points on the luminous source. The more nearly
