the concentration of nitric oxide preserved in the issuing gases does not usually exceed two parts per cent by volume, nitric oxide being capable of existence in an undecomposed but metastable condi- tion at temperatures below 1,000, by reason of the extreme slow- ness with which decomposition then proceeds.
Of the commercial plants employed, that due to Birkeland and Eyde has been described in 19.714. In the Schonherr type, the arc is struck between an internal electrode placed at the base of a tall vertical metal tube, which forms the second electrode, air being injected with a whirling motion vertically through the furnace. The arc is thus blown out into a flame, the length of which may be as much as 7 yards. The yield of nitric acid is stated to be about 75 grammes per kilowatt hour of energy used. The concentration of the nitric oxide in the issuing gases is 2-2-5%. A further type of " blown arc " furnace, due to Pauling, employs special lighting knives for promoting the formation of the arc.
The exit gases from any of the above types of furnace are cooled to about 50, and passed into a so-called oxidation chamber, in which the excess of oxygen combines with the nitric oxide, forming nitrogen peroxide, 2NO+O 2 = 2NO 2 . The nitrogen peroxide is subsequently absorbed by means of water in large granite absorp- tion towers, nitric acid being produced. The process is operated principally in Norway at Notodden and Christiansand.
In the Hausser process, the requisite high temperature is obtained by the explosion of compressed air with a fuel gas in the cylinder of an engine. Enrichment of the air with oxygen is stated (Green- wood, Industrial Gases, p. 107) to increase the yield of nitric acid. Thus, air containing 26% of oxygen gave a yield of 10 Ib. of nitric acid per 1,000 cub. ft. of combustible gas, compared with a yield of 6-4 Ib. with normal air. (E. B. M.)
NITTI, FRANCESCO SAVERIO (1868- ), Italian statesman, was born at Melfi (Potenza) in 1868. He had already become known as a barrister and as professor of financial science at the university of Naples, when he first entered Parliament in 1904. He made his reputation as an authority on economic and financial questions, and was Minister of Agriculture, Industry and Trade in the Giolitti Cabinet of 191 1-4. When the United States entered the World War in 1917 he was entrusted with an economic mission to that country, and certain of his utterances and acts in this connexion were severely criticized. He became Minister of the Treasury in the Orlando Cabinet from Oct. 1917 to Jan. 1919. On the fall of Orlando he succeeded him as premier, but his administration was a weak one, the Socialists and Communists being allowed to commit innumerable acts -of criminal violence with absolute immunity. He was closely associated with the post- war policy of svalutamento. The exasperation of the majority of the country at his policy, and the indignation aroused by his treatment of the Dalmatians in Rome, as well as his failure to secure a settlement of the Adriatic problem, led to his fall in June 1920, thus leaving the way open for the return of Giolitti. On his retirement from office he returned to journalism and business.
NIVELLE, ROBERT GEORGES (1856- ), French general, was born at Tulle (Correze) on Oct. 15 1856. He became a student at the Ecole Poly technique on Nov. 1 1876 (after having been entered at St. Cyr) and in 1878, as a sub-lieutenant, went through the course at the school of artillery and engineering. He was made a lieutenant in the igth Regt. of artillery in Oct. 1880 and was promoted captain on Dec. 29 1887. He became major (chef d'escadrons) in July 1901 and served on the China Expeditionary Corps staff during 1900-1. In 1908, while serving at Ozan, he was made a lieutenant-colonel, and three years later, while serving as chief of staff with the Algiers Div., was promoted colonel. In Dec. 1913 he assumed command of the 5th Regt. of artillery at Besancon and was so employed at the outbreak of the World War in Aug. 1914. At the head of this unit he took part in the operations of the 7th Corps in Alsace (including the battle of Dornach) and was specially mentioned in army orders. On Sept. 6 1914 on the 7th Corps front he again distinguished himself. The German pressure had compelled a French withdrawal and it seemed as if the 7th Corps would have to cross the Ourcq. Col. Nivelle, however, swiftly reorgan- ized his artillery and massed it at a vulnerable point. By the intensity of his fire he checked the German advance and enabled the French to recover the ground they had lost. Two weeks later, on the Aisne, he again saved a French withdrawal by skilful disposition of the artillery under his command. On Oct. 27 1914 he was promoted general of brigade. He commanded successively the 44th and 6oth Inf. Bdes. on the Aisne, and in Jan. 1915 was responsible for the check of the enemy before Soissons. On Feb. 19 following he took over the command of the 6ist Div.; becoming on Dec. 23 a substantive general of division and commander of the III. Army Corps. He went to Verdun at the end of March 1916 and a month later took over the II. Army. He planned the operations (executed by Gen. Mangin) which resulted in the reconquest in four and a half hours of the country S. of the line Thiaumont-Douaumont-Vaux-Damloup, country which the Germans had taken six months to capture and in the taking of which they had sacrificed some of their best troops. On Dec. 12 1916 he was made commander-in-chief of the armies of the N. and N.E.
The choice was inspired by a variety of motives, amongst which the most important were the objections, political and military, raised against more obvious candidates (such as Castelnau, Foch and Petain), and the feeling that a younger man might solve the problem of break-through which had defeated Joffre. Nivelle was put in command to break traditions and to win the war in the one great effort of which France, after all her losses, was still capable. He was the embodiment of the wave of optimism which swept over the Allied Govern- ments, armies and peoples in the spring of 1917. The story of his failure to realize these expectations need only be summarized here. Accepted by Mr. Lloyd George's Government as com- mander-in-chief not only of the French but also of the British front, he asserted his authority from the first moment in such a way as to antagonize Sir Douglas Haig's headquarters. When this difficulty had been officially smoothed over, he allowed him- self to be taken aback by the sudden withdrawal of the Ger- man centre in March 1917, which disconcerted nearly all the preparations for the Franco-British offensive. Next, persisting in a sanguine and grandiose offensive scheme to which many of his generals openly took exception, he found himself regarded with suspicion by his Government, and it was in the midst of a series of councils of war, inter-governmental negotiations, and internal incidents that he launched the attack of April 16 1917, a half victory which was the ruin of his hopes. Some weeks later he was dismissed from the command of the French armies. With the suspension of the offensive (which had already taken place), his command over the British forces had automatically ceased.
Later, Gen. Nivelle served as governor-general of Algeria.
Controversy of peculiar violence has naturally arisen in connexion with Nivelle's command and his offensive. On the general's side, Commandant de Civrieux's work is the principal source; on the other Jean de Pierrefeu's La verite sur I 'affaire Nivelle criticizes his actions from the standpoint of the Petain school. Less definitely critical works, which contain the most important documents and deal with the political aspects of the case, are H. Galli, L'offensive de 1917 and Mermeix, Les Crises du Commandement (pt. ii. Nivelle etPainleve).
NIXON, SIR JOHN ECCLES (1857-1921), British general, was born Aug. 15 1857 and joined the army in '1875. He was transferred to the Indian cavalry in 1878, and he served in the Afghan War, the Mahsud Waziri expedition of 1881, the Chitral relief expedition in 1895, for which he was promoted brevet lieutenant- colonel, and the Tochi operations of 1897-8. He was promoted colonel in 1899, and he commanded a column during the later stages of the South African War and was given the C.B. for his services. Promoted major-general in 1904, he was inspector-general of cavalry in India from 1906-8, and he then held various higher commands in that country (being promoted lieutenant-general in 1909 and general in 1914) till in April 1915 he was sent to Mesopotamia to take charge of the campaign there. Under his auspices Gen. Townshend advanced successfully up the Tigris to Kut; but Nixon was largely responsible for the subsequent abortive attempt to reach Bagdad, which led to the retreat from tesiphon and to the investment of Kut. He fell ill towards the end of 1915 and quitted the theatre of war. In 1919 he was given the G.C.M.G. in recognition of his services four years earlier, and he retired in that year. He died at St. Raphael, France, Dec. 15 1921.
NOBLE, SIR ANDREW, BART. (1832-1915), British physicist and artillerist (see 19.730), died at Ardkinglas, Argyllshire, Oct.
