ARRAS, BATTLES OP 272 ARRIAGA large commerce in cotton and stuffs, hosiery, lace, pottery, etc. Arras has been the theater of many memorable historical events, and was fortified by Vauban,in the reign of Louis XIV, Robes- pierre was born here, as was also Da- miens, the assassin of Louis XV. Dur- ing the Middle Ages, Arras was famed for its tapestry, richly figured hangings that adorned the halls of the kings and the nobles. They were known under the name of arras; but have been for a long time superseded by the tapestry of the Gobelins. Arras was the capital of the Celtic Atrebates (whence the name), and consequently of the province of Artois. As such it was long a part of Burgundy. It was ceded to France in 1482; attached to Austria in 1493; and finally became French in 1640, when Louis XIII. took it after a long siege. In the World War the town was wrecked by bomdardments. The Ger- mans attacked the place three times in October, 1914. From Oct. 20 to 26 Arras was under heavy fire. Eventually the French under General Maud'huy drove the Germans back so far that their howitzers could no longer threaten the town. Pop. about 26,000. ARRAS, BATTLES OF, a series of im- portant engagements in the World War which took place in the neighborhood of the city of Arras, France. This area, from the autumn of 1914, following the German attempt to break through the Allied lines to the channel ports, was the scene of almost continual operations. The city itself was exposed to repeated bombardments and was almost com- pletely destroyed. The most important offensive in the vicinity was undertaken by the British in the spring of 1917. It was carried on a 12-mile front N. and S. of AiTas, and was gradually ex- tended to an offensive over the whole line from Arras to St. Quentin. The defense was prepared by an artillery bombardment which lasted four days. On the fifth day of the battle the Cana- dian troops stormed Vimy Ridge, cap- turing 4,000 prisoners and large quan- tities of war material. The advance continued on April 11 when Monchy and other towns were captured. On April 13 the British swept forward from a new position E. of Arras and drove the Germans back on a 12-mile front, captur- ing six villages and seriously threaten- ing the city of Lens. The outskirts of that city were entered on April 15. After a pause of several days, the Brit- ish on April 24 pushed forward E. of Monchy. Three days later they broke the Oppy Une, a switch of the Hinden- burg line. On May 3 they captured Fresnoy and a part of Bullecourt, but were later obliged to give these up. The battle reached a standstill on May 15, 1917. The British were driven back, in the first two weeks of June, E. of Loos. The chief effects of the battle, aside from the capture of over 15,000 Germans and 200 guns, was the placing of Lens im a pocket which constantly tightened until its final capture by the British. See World War. ARRHENATHERUM, a genus of plants belonging to the order grami- ruicese, or grasses. A species g^rows wild in England, A. avenaceum, or tall, oat- like grass. It is also cultivated occasion- ally in England, and much more fre- quently in France, but is not very nutri- tious. ARRHENIUS, SVANTE, a Swed- ish chemist, bom in 1849 near Upsala. He was educated in the university of that city and, after teaching for a short time, spent several years abroad carrying on original investigations in physical chem- istry. In 1891 he became professor at the University of Stockholm. His con- tributions to the study of electrolytic phenomena and the chemical and physi- cal properties of substances are of the utmost importance. He established the so-called theory of electrolytic dissocia- tion. Arrhenius wrote much on chem- ical subjects and in 1907 published a series of lectures delivered at the Uni- versity of California. In 1903 he re- ceived the Nobel Prize for chemistry. Perhaps his most popular work is "Worlds in the Making" (1908), in which he combatted the theory that the universe is tending to destruction by loss of heat and motion. ARRIA (ar'e-a), a celebrated Roman matron, wife of Cascinna Paetus, consul during the reign of Claudius, about A. D. 41. Pjetus having raised an unsuccess- ful revolt against Claudius, in lUyria, was condemned to die. He was, however, allowed the option of ending his life by suicide, which the Romans did not deem a crime. Psetus hesitated; Arria seized the dagger, plunged it into her bosom, and then presenting it to her husband, said, "It is not painful, Paetus." This, with other instances of her conjugal de- votion, has immortalized her. ARRIAGA, MANOEL DE, a Portu- guese statesman, born in 1842 at Horta in the Azores. He was educated at the University of Coimbra, and after study- ing law he practiced in Lisbon. For many years he was a member of the Chamber of Representatives as a Re-