prevents the bolt from being blown to the rear. When the pressure is reduced, the adhesion ceases, and the lock, actuated by the remaining pressure, automatically slides upward and clear of its retaining shoulder while the bolt moves rearward against the recoil spring (102) and cocks the firing pin.
When the weapon is cocked the entire bolt group is held by the sear (104) in a retracted position, as shown in fig. 17. On the trigger being pulled the bolt, driven forward by the recoil spring, pushes a cartridge into the chamber. During the forward motion of the bolt the hammer (103) strikes a shoulder of the receiver and rotates on the hammer pin, its top end strikes the firing pin and the cartridge is fired. Firing is discontinued by releasing the trigger; the sear (104) then engages the bolt in its retracted position, leaving the chamber empty. By means of the disconnector (105) the weapon 'can be made semi-automatic at will. When the magazine is emptied, the trip (106) allows the sear to engage the bolt in a rear position ready to feed and fire again when the trigger is pulled. Sights graduated to 600 yd. are provided.
The sub-machine-gun is intended as an auxiliary weapon for trench use and for close fighting generally. It has been adopted also by the police of several American cities for use as a riot weapon, both for shot and ball cartridges. (H. O'L.)
RIGHI, AUGUSTO (1850-1920), Italian physicist, was born at Bologna Aug. 27 1850. Details of his experimental work in magnetism and the problems of electricity and light are given in 17-389, 391 and 346, 6.859, 9-206, 21.936. He was specially noted for his discovery of the electrical conductivity of bismuth and other metals, and for his pioneer work in wireless telegraphy. G. Marconi was his pupil. He died at Bologna, June 8 1920.
RILEY, JAMES WHITCOMB (1853-1916), American poet
(see 23.343), died at Indianapolis, Ind., July 22 1916. In 1915, by proclamation of the governor of Indiana, his birthday, Oct. 7, was observed throughout the state, in honour of "Indiana's most beloved citizen." In 1913 he issued in six volumes a biographical edition of his works.
See Clara E. Laughlin, Reminiscences of J. W. Riley (1916).
RIO DE JANEIRO (see 23.353). According to the census of 1920, the pop. of the independent municipal commune, or federal district, which contains the city and is detached from the province of the same name, was 1,157,873 inhabitants. As the census of 1906 showed 811,443 inhabitants, the pop. has increased 43% in 14 years, an annual increment of 3-05 per cent. In 1920 there were 1,265 factories, large and small, with 46,953 operatives, representing a capital of nearly 270,000,000 paper milreis, and an annual production valued at about 500,000,000 milreis. In 1920 the number of buildings in the municipality was about 113,000, as against 84,375 m 1906- The federal district is governed by a prefect appointed by the president of the republic, and elects three senators and ten deputies to the national congress. The legislative power of the municipality is vested in a council consisting of 24 inlendentes elected for three years.
The consolidated debt of the municipality in 1920 was computed at 227,089,200 paper milreis, of which 129,225,450 milreis was an external debt, and 97,863,750 milreis internal. The revenue had grown from 29,070,883 paper milreis in 1910 to 51,182,357 paper milreis in 1919.
Education. Primary instruction is provided by the municipality, which in 1920 maintained 320 day-schools and 68 night-schools, with a matriculation of 74,111 pupils in the former and 8,662 in the latter. There are in addition 236 elementary private schools, with 19,825 pupils; over 80 receive a subvention from the Government on condition that they adopt the official curriculurrrand admit a cer- tain number of children free. Secondary instruction is cared for in public lycees and in many private establishments. There is no university, but the capital possesses higher faculties of law, medicine and engineering, besides schools providing instruction in pharmacy, dentistry, commerce, music, dramatics and the fine arts. The na- tional Government also maintains a naval academy, a military col- lege and a preparatory school of tactics. The most important libraries are: the National library, the best appointed in S. America; the Municipal ; the Gabinete Portuguez da Leitura ; that of the Lycfe of Arts and Crafts; and the collections existing in the various minis- tries and departments.
Streets and Buildings. During the decade 1910-20 the ambitious programme of municipal improvements inaugurated in 1903 was in large measure completed. The port works, including a sea-wall over 2 m. long, 8 ft. above mean high-tide, and lying almost entirely in deep-water, enclosing a broad reach of reclaimed land between it and the former shore-line, provide the city with the most modern facilities for loading and unloading ships. The Avenida Rio Branco (formerly Avenida Central), built through the heart of the city in 1904, is now one of the handsomest thoroughfares in the western hemisphere. Over a mile long from N. to S., it is lined with fine private and public buildings. The military, naval and jockey clubs are situated there, and also the offices of some of the principal news- papers, such as the Jornal do Comercio and O Paiz, besides many fashionable shops, caf and business places. At the southern end is a group of elegant State edifices, the Municipal theatre, the Monroe palace, and the National library and Academy of Fine Arts. It is adorned with three rows of trees, and with broad sidewalks of white and black stone set to form figures in mosaic, as in Lisbon. For this both material and workmen were imported from Portugal. The Municipal theatre, designed in 1904, cost over 2,000,000, al- though it seats but 1,700 people. The building which houses the National library, opened in 1910 in commemoration of the centenary of its founding (1808), is also a notable addition to the city. It is a fireproof structure of granite, marble and steel, equipped with every modern library appliance.
One of the important developments of Rio de Janeiro has been in suburban road-building. As the hills come practically to the bay and sea, construction is difficult, but great progress has been made and a 4O-m. motor drive over perfect roads is now joining all the famous beaches with Tijuca and the city. The magnificent bayside drive, the Avenida Beira-Mar, with its double motor track and intervening lawns and gardens, is particularly remarkable.
Sanitation. The city, formerly a hotbed of yellow fever and smallpox, has become one of the healthiest tropical cities in the world. The death-rate has fallen to about 20 per 1,000. This is the result of a campaign of scrupulous cleanliness, rigid enforcement of sanitary measures and scientific eradication of mosquitos and other germ-bearing insects, inaugurated under the direction of the celebrated Brazilian scientist, Dr. Oswaldo Cruz, in the first admin- istration of President Rodrigues Alves (1903). In 1920 a law was passed by Congress creating a national department of public health, consisting of three divisions, one in charge of the federal capital. (C. H. H.)
RIO DE ORO (see 23.357). The area of the Spanish Sahara
denned and extended by the Franco-Spanish Conventions of
1904 and 1912 is about 110,000 sq. miles. The frontiers have
not been delimited. The colony proper (area, about 65,500 sq.
m.) extends from lat. 2i2o' N. to 26 N. The 1904 Agreement
recognized a Spanish Protectorate over an area on the N. of
about 34,700 sq. m., extending to lat. 274o' N. and bounded E.
by the meridian 84o' W.; and the 1912 Agreement acknowledged
the sovereign rights of Spain over this region. Still farther N.
is an " occupied territory " of about 9,800 sq. m., extending to
Wad Draa (lat. 284s' N.), and forming an intermediate zone
between the Spanish possessions and Morocco.
The interior has been little explored. A central volcanic table- land, the Tiris, about 1,000 ft. above sea-level, falls by terraces broken by ravines to the coastal plain and to the Segiet el Hamra on the north. To the S., the vast dunes of Azefal separate the Spanish Sahara from Mauretania (see 17.908). Wad Shebika enters the sea about 36 m. S.W. of Wad Draa and runs parallel to its lower course. The only permanent water is in brackish wells which frequently become choked. The only district likely to repay colonization ap- pears to be the wide basin of the Segiet el Hamra and its tributaries, whose flood-waters suffice to fertilize pasture and arable land or date-groves, as at the oasis of Smara.
There are few main tracks and a network of smaller tracks, but no roads and but few villages. Smara, 160 km. inland from C. Juby, is the most important settlement and is the headquarters of the notorious religious agitators Ma el 'Ainin and his son El Hiba. Vil Cisneros, on the Dakhla peninsula, the residence of the governor (deputy for the governor-general of the Canaries), has a garrison and fish-curing industry; pop. (1918) 529 foreigners and 495 natives, with an adjoining village of 800 negroid half-castes (Imragen). The desert population, roughly estimated at 80,000, is nomadic, fluctuating between French and Spanish territory, and is split up into pro-French and pro-Spanish partisans. In 1912, there was a general rising under LI Hiba. In 1916, a small Spanish expedition occupied C. Juby, but the fishermen, of whom the chief are the Aulad Delim Arabs and their allies the Regeibat (Arabized Berbers), remained practically uncontrolled. Camels and ostriches are reared.
In 1916 the total value of imports by sea was 4,820; of exports 4,910, chiefly fish and fish products. The fishing industry would be considerable if better methods were employed. There are open roadsteads at El Msit, at the mouth of the Segiet el Hamra, and Tarfaya, about iSokm. farther north. The climate is fairly equable on the coast, but intense heat and drought prevail inland, with diurnal variations of temperature in the shade of as much as 74. At Villa Cisneros the mean maximum summer temperature is 86 F., and the mean minimum winter 48 F. (E. G. S.)
RISLEY, SIR HERBERT HOPE (1851-1911), English anthropologist, was born at Akeley, Bucks., Jan. 4 1851. Educated at
