Locomotive Construction'; Peabody and Miller, 'Notes on Steam Boilers'; R. H. Thurston, A Manual of Steam Boilers,' and 'Steam Boiler Explosions'; William Kent, Steam Boiler Economy; W. H. Shock, Steam Boilers'; Leslie S. Robertson, 'Water Tube Boilers; and W. H. Ford, Boiler Making. See also the 1899 Code for boiler trials, in Vol. 20 of the 'Transactions of the American Society of Mechanical Engineers.' A. D. RISTEEN,

Hartford Steam Boiler Insp. and Ins. Co.

Boiling Point, the temperature at which a liquid boils, when exposed to a definite pressure, which is understood to be the ordinary atmospheric pressure, in the absence of any specific statement to the contrary. When a liquid is freely exposed to the air, evaporation goes on constantly from its surface, the heat required being absorbed from surrounding bodies. If the liquid is warmed, the evaporation goes on at an increased rate; but as its temperature is increased by the application of heat, there comes a time when mere superficial evaporation cannot take care of all the heat supplied. Bubbles of vapor then form within the body of the liquid, and the liquid is said to have attained its "boiling point." If the supply of heat be now increased, it is found that the temperature of the liquid remains stationary; bubbles merely form more rapidly, so that the rate of loss of heat through evaporation is still maintained equal to the rate of supply. The temperature of boiling depends upon the pressure; for at an increased pressure the bubbles are formed in the interior of the liquid with greater difficulty, and therefore not until a higher temperature is attained. The variation from this cause is considerable. Thus the boiling point of water, under a pressure of one atmosphere, is 212° F., while under a pressure of two atmospheres it is about 250° F. At the reduced pressures prevailing on the tops of mountains, the boiling point of water is lower than 212° F., and advantage of this fact is taken for determining the heights of mountains by observations of the boiling point at their summits. (See HYPSOMETRY.). When the liquid is not open freely to the air, but confined in a closed vessel, its temperature can be raised indefinitely by the application of heat, but the vapor in the space above it is denser, and has a greater pressure, at higher temperatures. The correspondence between pressure and temperature, under these circumstances, is very exact, although no simple law connecting the two is known. Rankine gave an empirical formula for the relation between them, of which computers of steam tables have made great use Miscellaneous Scientific Papers, page 1); but the physical significance of this formula is unknown. The relation between the pressure and boiling point of a liquid is commonly exhibited by means of a table in which the temperatures of ebullition are set down opposite the corresponding pressures. (For a table of this sort for water, see STEAM.) The phenomena described above in connection with the free evaporation from a liquid exposed to the air are in general true, but certain qualifications must be made, under certain special conditions. Thus, it is difficult to induce water to boil when it has been freed from dissolved air; and in the entire absence of such air De Luc found that water can be heated as high as 234° F., under ordinary

Vol. 3-7

atmospheric pressure, before boiling, if the experiment is performed with proper care. A liquid thus heated to a temperature in excess of the normal boiling point corresponding to the pressure to which it is subjected is said to be "superheated." When boiling does finally occur in a superheated liquid, it takes place with almost explosive suddenness, and the loss of vapor is exceedingly rapid for a moment or two, until the temperature of the liquid has been reduced by this means to the normal temperature corresponding to the pressure prevailing at the time. The temperature at which ebullition takes place is also influenced to a certain extent by the nature of the vessel in which the liquid is heated. Thus Marcet found that in a glass vessel which had been carefully washed out with sulphuric acid, and then well rinsed, pure water does not boil until a temperature of 223° F. has been attained. All results of this kind are of an indefinite character, however, since they relate to the temperature at which boiling first begins, rather than to the state in which the liquid and its vapor are in a condition of permanent thermal and mechanical equilibrium. Superheated water is in an unstable state, and, according to some authorities, not a few boiler explosions have been due to the superheating of the water present, from some cause, and the subsequent explosive liberation of steam, as the water returned to its normal condition; but this notion concerning the cause of boiler explosions has never been substantiated by experiment or otherwise, and must be regarded as a mere speculation, without any foundation in fact. A liquid has a higher boiling point, when it contains some substance in solution, than it has when pure. The effect of dissolving salt or any other electrolyte is complicated by the occurrence of dissociation (q.v.); but for dilute solutions of non-electrolytes, like sugar, the following law, first given by Raoult, holds true: If a series of dilute solutions of such substances be prepared, each solution containing, per unit weight of the solvent, an amount of solid proportional to the molecular weight of the solid, then the solutions so prepared will all boil at the same temperature. (See SOLUTIONS.) For marking the "boiling point" upon thermometers, it is the universal practice to expose the thermometers to the steam rising from the boiling water, rather than to immerse them in the water itself; for the temperature of the steam is independent of the presence of traces of dissolved substances in the water, and also of the action of such accidental or irregular causes as the superheating of the water. See THERMOMETRY.

bwä'ye, French painter: b. La Bassée, France; Boilly, Louis Leopold, loo-e la-ō-põld about 5.000 paintings, chiefly historical. The d. 1845. To his prolific brush are attributed period represented on his canvases ranges from the time of Louis XVI. to the end of the Restoration. Among his works are: Arrival of the Diligence (1803); and 'Isabey's Atelier.'

Bois d'Arc, bwä-därk, the osage orange (q.v.).

Bois de Boulogne, bwä-de boo-lo-ny, once a forest abounding with game near the gates of Paris, now a beautiful park belonging to the city; area, 2.250 acres. The greater part of the old trees were destroyed during the revolution. When Napoleon chose St. Cloud for a summer

it to Schleissheim, and in 1835 most of the paintings were sent to Munich. A lithographic work on this collection was published in 40 parts between 1821 and 1840. See Sulpiz Boisserée,' a biography (1862).

Boissier, Marie Louis Gaston, mä-re loo-e gäs-tôn bwä-syā, French archæologist and historian: b. Nimes, 15 Aug. 1823. After studying at the Ecole Normale he was an instructor in rhetoric in his native city 1847-57; professor of Latin eloquence and literature at the Collège de France from 1861, was elected to the French Academy in 1876 and to the Academy of Inscriptions and Belles-lettres 1886. His literary style has been much praised for its clearness and beauty. His works comprise 'Le poète Attius' (1857); 'Etude sur la ire et les ouvrages de Terentius Varron' (1861); La religion romaine d'Auguste aux Antonins' (1883); 'Lafin du paganisme' (1894); Cicéron et ses amis' (1892); and Promenades archéologiques Rome et Pompéi (1892); the two last named being marvelously accurate and vivid reconstructions of the antique spirit and atmosphere. Other works are: Roman Africa,' and 'The Country of Horace and Vergil.'

Boissieu, Jean Jacques de, zhon zhäk bwäsye, French painter and engraver: b. Lyons, 1738; d. there in 1810. He was intended by his parents for the magistracy, but manifested such a decided inclination for drawing that he was allowed to follow it. After remaining for some time at Lyons, and painting some excellent imitations of the Flemish school, he visited Paris, where his intimacy with the most celebrated artists of the time enabled him greatly to improve his style. On his return to Lyons he devoted his attention chiefly to engraving. He afterward accompanied the Duc de Rochefoucauld to Italy, and having studied the works of the great masters with the greatest assiduity, resumed painting; but as the use of oil injured his health, he, shortly after his return to France, abandoned it finally for engraving, in which his reputation soon became European, and his works were eagerly purchased by the most wealthy and distinguished amateurs. His engravings amount to 140 plates, among which that of Le Charlatan,' after a picture by Karel Dujardin, is considered his masterpiece.

Boissonade, Jean François, zhon frän-swa bwä-so-nad, French classical scholar: b. Paris, 12 Aug. 1774; d. Passy, 8 Sept. 1857. He was educated at the Collège d'Harcourt, and at the age of 18 was attached to the ministry of foreign affairs. He subsequently became a contributor to periodical literature in the Magasin Encyclopédique of Millin and the Journal de l'Empire, the precursor of the Journal des Débats. Ancient and modern literature, both French and foreign, grammatical criticism, bibliography, and natural sciences occupied his pen. In 1813 he was admitted a member of the Academy of Inscriptions and Belles-Lettres. He afterward wrote about 150 articles for the 'Biographie Universelle.' He became, in 1809, assistant of Larcher, as Greek professor of the faculty of letters in Paris, and four years afterward he succeeded him both in the faculty and in the institute. Finally, in 1828, he was called to the chair of Greek literature in the College of France. From this time he devoted himself entirely to his duties as a professor, and his

labors as a classical editor. He has produced no complete work in French, but is said to have written Latin with natural grace and elegance, and his editions of the classics are highly esteemed. His editorial labors were also extended to a few French works, and he translated a heroi-comic poem, the "Genpillen," from the Portuguese.

Boissy d'Anglas, François Antoine, fränswä än-twän bwä-se dän-glas (COMTE DE), French statesman of the revolutionary period: b. Saint Jean-la-Chambre, near Annonay, 1756; d. Paris, 20 Oct. 1826. He studied at Annonay, and was admitted as an advocate to the parliament of Paris. In 1789 he was elected to the States-General where he was a moderate advocate of revolutionary principles, in support of which he wrote at this time various brochures. In 1792 he was returned as a deputy to the convention. He voted against the death of Louis XVI., and after the fall of Robespierre he was appointed secretary of the convention, and a member of the Committee of Public Safety. He was created a peer by Louis XVIII. in 1814, but supported Napoleon during the Hundred Days, and was consequently expelled from the peerage by a royal ordinance, but shortly afterward reinstated. He was from 1803 a member of the consistory of the Reformed Church, a member of the Institute from its commencement, and on its reconstruction in 1816 he became a member of the Academy of Inscriptions. He wrote an essay on the life and writings of Malesherbes (1819-21); 'Etudes Littéraires et Poétiques d'un Vieillard' (1825).

The fame of Boissy d'Anglas rests chiefly on a scene in the convention in 1795, when the hall was invaded by an angry mob demanding bread and the Constitution of 1793. Called temporarily to take the chair, in the absence of the president, Boissy had presented to him the head of a deputy, Féraud, which had been cut off by the insurgents and placed on the end of a pike. He saluted it, and continued calmly facing the mob, and to his courage and firmness the safety of the convention at this crisis is attributed. Such is the popular version of a story of which the most various and contradictory accounts are given. It has been said that Boissy d'Anglas exhibited no such courage as has been attributed to him, and that he was merely kept in his place by the pressure of the mob. His enemies, who accused surrection was started by the reactionary party to him of reactionary tendencies, even said the indiscredit the revolution, and that Boissy was in understanding with the leaders of the mob. For this last accusation there appears to be no foundation, but it is quite likely the scene may have been represented in a more dramatic form than as it actually occurred.

Boito, Arrigo, ä-rē'gō bō-e'tō, Italian composer: b. Padua, 24 Feb. 1842. His great work, the opera 'Mefistofele,' occupied him for nearly 20 years. The garden scene was written while he was a student in the Milan Conservatory in 1856, and the score was finished for the stage in 1868, the composer having done much literary work in the interim and lived variously in France, Germany, and Poland. On 5 March 1868, 'Mefistofele was sung at La Scala, Milan, the performance lasting six hours, much interrupted by hissing and applause, and its failure was evident. Boito then remodeled the opera,

and in 1875 it was produced at Bologna with great success. It was sung in other cities with equal success, but it has never been a popular opera in the full sense of the word. În 1883 it was produced at the New York Metropolitan Opera House with Campanini and Nilsson in the cast and was revived in 1896 and again in 1901. The opera is considered one of the most important of modern Italian operas, marking, as it does, the precise point where the modern school of Italian composition, illustrated by the later works of Verdi, Mascagni, Puccini, etc., diverges from the work of the Bellini and Donizetti school. Boito's other operas, (Ero Leandro'; Nerone'; and Orestiade' have never been sung.

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Boivin, Marie Anne Victoire, mä-re an vic-twär bwä-văn (GILLAIN), French midwife, upon whom a diploma of M.D. was conferred by the University of Marburg, noted for her writings on obstetrics: b. Montreuil, 9 April 1773; d. 16 May 1841. She was educated in a nunnery, where by her talents she attracted the attention of the sister of Louis XVI., Madame Elisabeth. When the nunnery where she was placed was destroyed in the course of the revolution, she spent three years in the study of anatomy and midwifery. In 1797 she married an employee at Versailles, of the name of Boivin, but on being left after a short time a widow with a child and without fortune, undertook the office of midwife at the Hospital of the Maternity, and, in 1801, was appointed chief superintendent of the institution, to which, in accordance with her suggestion, a special school of accouchement was added by Chaptal. Her 'Mémorial de l'art des accouchements,' published in 1824, passed through several editions. The empress of Russia invited her to St. Petersburg, but she declined.

Bojaca, bō-zhä'ka, Battle of, so called from having been fought near the bridge of the small town of Bojaca, not far from the city of Tunja, between the Spaniards under Barreyro, and the united forces of Venezuela and New Granada, commanded by Bolivar. It occurred 7 Aug. 1819, and was decisive of the independence of New Granada. Among the Republicans, Gens. Anzuategui, Paez, and Santander distinguished themselves; and the Spaniards sustained a total defeat, their general, most of their officers and men who survived the battle, together with all their arms, ammunition, and equipments, falling into the hands of Bolivar. So complete was the destruction of the Spanish army, that the viceroy instantly fled from Santa Fé, leaving even the public treasure a prey to the

conquerors.

Bojador, bō-zha-dôr', Cape, a promontory on the west coast of Africa; lat. 26° 7' 10" N.; lon. 14° 29′ W. It is one of the projecting points of the great desert of Sahara, and forms the west extremity of a rocky ridge called the Jebel-khal or Black Mountain. The coast north of this cape is extremely dangerous, being shallow to a great distance out, and constantly enveloped in a haze. It has been, in consequence, the scene of many a melancholy disaster. Cape Bojador was long the limit of navigation toward the south and was first passed by the Portuguese in 1433.

Bojol', Philippines, an island north of Mindanao, about 40 miles long by 30 miles wide. It is woody and mountainous. Rice and gold are its chief productions. Pop. 187,000.

Bok, Edward William, American editor: b. Helder, Holland, 9 Oct. 1863. He came to the United States in infancy, and was educated in the public schools of Brooklyn. He has edited the Ladies' Home Journal, and written The Young Man in Business,' and 'Successward.'

dramatist: b. Philadelphia, Pa., 6 Oct. 1823; d. Boker, George Henry, American poet and there, 2 Jan. 1890. He graduated from Princeminister to Turkey in 1871-5, and to Russia in ton in 1842; studied law; and was United States 1875-9. His plays include: Calaynos' (1848); Anne Boleyn (1850); Francesca da Rimini'; The Betrothed'; and All the World's a Mask. He published also 'Poems of the War) (1864); Königsmark and other Poems (1859); The Book of the Dead' (1882); and Sonnets' (1886); Francesca' is his best play and has been several times put upon the stage by Barrett and other actors.

Bokelmann, Christian Ludwig, krist-yăn lood-vig bō'kel-man, German painter: b. Saint Jürgen, 1844; d. 1894. He was a pupil of Wilhelm Sohn at Dusseldorf and became distinguished as a genre and portrait painter. Among his works are: 'House of Sorrow' Pawnbroker's Shop'; 'Opening of the Will; 'Portrait of Klaus Groths.'

Bokhara, bo-kä'ra, a khanate of Central Asia, practically vassal to Russia, bounded on the north by Russian Turkestan, west by Khiva and the Russian Trans-Caspian territory, south by Afghanistan, and east by Russian Turkestan. It formerly occupied considerably more territory than now, having been reduced by the conquests and encroachments of Russia, which have been only partially compensated by some additions. The present area of the khanate is estimated at about 92,000 square miles. The country is to a great extent occupied by deserts and low and naked ranges of mountains, and the cultivated portions of it are confined to the valley of the rivers, especially the Oxus or Amoo Daria, which forms the southern boundary for a considerable distance, and then flows from southeast to northwest parallel to and not far from the frontier of the country. Bokhara lies between lat. 37° and 41° N., and in greater part is no more than 1,100 or 1,200 feet above the level of the sea, but in the extreme east is mountainous. The climate is subject to great extremes, being warm in summer and very cold in winter. There is very little rain, on which account it is necessary to resort to artificial irrigation. Besides cereals, cotton, tobacco, and vegetables are cultivated, and there is abundance of fruit. The total population amounts to about 2,250,000, and consists of the Uzbecks, who are the ruling race, and to whom the emir belongs; the Tajiks, who form the majority in the capital; the Kirghizes, less numerous than the Tajiks; about 60.000 Arabians, descendants of the soldiers who were brought into the country by the third caliph of Bagdad on the occasion of the conquest of Turkestan: Persians who have chiefly been brought as slaves to Bokhara: Turcomans, Hindus, and about 10.000 Jews who live in the towns beyond the protection of the law, and accordingly oppressed by the other inhabitants. Since the

separation of Samarcand there are now only two towns of importance in Bokhara, namely, the chief town Bokhara, with a population of about 60,000; and Karshi, with about 25,000. Besides these there are a few small towns and some hundred villages in the country. The capital, according to Vámbéry, the centre of Tartar civilization, is ill built and has a gloomy aspect, and in luxury of dress and mode of life is far behind the towns of western Asia. Among the people there reigns the utmost moral corruption along with a rigorous adherence to outward forms. The country is distinguished from the other countries of Central Asia by its numerous schools, and in the same proportion by the amount of culture diffused among the people generally; but the women are even more degraded than in other Mohammedan countries. The rule of the emir is absolute, though he is to some extent under the influence of the clergy. The manufactures are unimportant, but there is a very considerable caravan trade, cotton, rice, silk, and indigo being exported, and woven goods, sugar, iron, etc., being imported. There is also now a trade by railway, since the making of the line from the Caspian to Samarcand. Bokhara is remarkable for its religious fanaticism, and various European travelers have been exposed to danger. After Alexander Burnes had visited Bokhara on a commission from the government of India in 1832, the British ambassador in Teheran sent Col. Stoddart in 1838 to obtain from the Emir Nasrulla the deliverance of the Russian prisoners that he had taken on his predatory incursions into Russian territory. Nasrulla, however, irritated at the neglect to answer his letter to the queen of England, ordered Col. Stoddart to be thrown into prison, and after treating him with great cruelty, compelled him to acknowledge the Mohammedan creed. Capt. Conolly, who had been with a similar object in Khiva and Khokand, came in 1841 to Bokhara, and after having to submit to the same treatment as Col. Stoddart, was executed along with him in 1842. Information of their fate was brought to Europe by the missionary Wolff, who had been sent to Bokhara in 1843 for this purpose.

In 1850 the Russians established themselves at the mouth of the Sir (Jaxartes), where it flows into the Sea of Aral, and in 1864 they found it necessary to proceed farther up the river. They_made themselves masters of the two towns Turkestan and Aulie-ata, and after bringing them into communication with one another, invested Chemkend, Niazbek, and Chinab. The land thus occupied, which up to that time had formed the northern half of the khanate of Khokand, was, along with some other districts that had previously been annexed to Russia, erected into the Russian government of Turkestan, and incorporated with the general government of Orenburg, by the ukase of 14 Feb. (26) 1865. By a subsequent ukase, dated 11 July (23) 1867, this territory was constituted a general government. Soon after the khan of Khokand invaded the Russian territory, in consequence of which the Russians advanced still farther south and attacked Tashkend, which they took on 28 June 1865. They - did not, however, incorporate Tashkend with the Russian territory, but declared it an independent khanate under the protection of Russia. This arrangement was opposed by Muzaffer

Eddin, Emir of Bokhara, whereupon the Russian general Romanovski again assumed the offensive, and marching into Bokhara took Khojend by storm on 5 June 1866. In this way Russia came into the possession of the whole basin of the Sir. Not long after Tashkend was incorporated with the Russian territory by the desire of the inhabitants. Meanwhile the war with Bokhara still went on, and peace was not concluded till the beginning of 1867. This peace, however, did not last long. The war was renewed in the spring of the following year, and it was only in July 1868 that the terms of peace between Russia and Bokhara were finally agreed upon. Bokhara was to give up Samarcand and Katti Kurghan, along with the surrounding districts (constituting the tract of land watered by the Zerafshan), and at the same time promised to pay an indemnity to Russia and to protect her trade. Since then the peace has not been broken, but the Emir of Bokhara has sunk more and more into a position of entire dependency on Russia. During the autumn the Russians intervened against the emir's son, who had risen in revolt against him, and on 12 October in the following year the emir sent an embassy with presents (tribute) to the czar at St. Petersburg. In the meantime Muzaffer-Eddin had fallen into a dispute with Afghanistan. Shere Ali Khan, of Kabul, had given a favorable reception to the rebellious son of the emir, and Muzaffer-Eddin, probably in consequence of encouragement from Russia, now thought himself able to make good his former claim to Badakshan, and the territory lying about the sources of the Oxus, especially since the Khan of Kabul seemed to have but a slight hold of these parts. He had accordingly already sent out an army with the view of conquering those parts, when, toward the end of 1869, pressure being put upon him by Russia, he concluded a treaty with Kabul by which the Oxus was fixed as the boundary of the conterminous states, and this boundary was afterward recognized by Russia and England. After the Russian expedition to Khiva in 1873 an agreement Iwas made between Russia and Bokhara on 28 September of that year, according to which Bokhara received a portion of the territory that had been ceded by Khiva to Russia, while the Russians received various privileges in return. Muzaffer-Eddin died in 1885, and was succeeded by his son Abd-ul-Ahad. Bokhara will probably be ultimately completely placed under Russian administration, for what little power it had lapsed in 1884 by the practical absorption of the country, resulting from the annexation of Merv. Since 1885 the troops, which were formerly ill trained and badly armed, have been drilled by Russian instructors and armed with rifles. See Le Messuner, 'From London to Bokhara' (1899); O'Donovan, 'The Merv Oasis' (1880); Curzon, 'Russia in Central Asia' (1889).

Bokhara, the capital of the khanate of the same name, in lat. 39° 48' N.; lon. 64° 26' E. It is eight or nine miles in circuit, and is surrounded by a mud-wall. It is poorly built, consisting of extremely narrow streets and paltry houses. The principal edifices are the palace of the khan, crowning a height near the centre of the town and surrounded by a brick wall 70 feet high; and numerous mosques, the largest of which is enameled