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towards the year 1505, the portrait of the doge Loredano in the National Gallery, the only portrait by the master which has been preserved, and in its own manner one of the most masterly in the whole range of painting.

The last ten or twelve years of the master's life saw him besieged with more commissions than he could well complete. Already in the years 1 501-1 504 the marchioness Isabella Gonzaga of Mantua had had great difficulty in obtaining delivery from him of a picture of the "Madonna and Saints" (now lost) for which part payment had been made in advance. In 1505 she endeavoured through Cardinal Bembo to obtain from him another picture, this time of a secular or mythological character. What the subject of this piece was, or whether it was actually delivered, we do not know. Albrecht Dürer, visiting Venice for a second time in 1506, reports of Giovanni Bellini as still the best painter in the city, and as full of all courtesy and generosity towards foreign brethren of the brush. In 1507 Gentile Bellini died, and Giovanni completed the picture of the "Preaching of St Mark" which he had left unfinished; a task on the fulfilment of which the bequest by the elder brother to the younger of their father's sketch-book had been made conditional. In 1513 Giovanni's position as sole master (since the death of his brother and of Alvise Vivarini) in charge of the paintings in the Hall of the Great Council was threatened by an application on the part of his own former pupil, Titian, for a joint-share in the same undertaking, to be paid for on the same terms. Titian's application was first granted, then after a year rescinded, and then after another year or two granted again; and the aged master must no doubt have undergone some annoyance from his sometime pupil's proceedings. In 1514 Giovanni undertook to paint a Bacchanal for the duke Alfonso of Ferrara, but died in 1516, leaving it to be finished by his pupils; this picture is now at Alnwick.

Both in the artistic and in the worldly sense, the career of Giovanni Bellini was upon the whole the most serenely and ́unbrokenly prosperous, from youth to extreme old age, which fell to the lot of any artist of the early Renaissance. He lived to see his own school far outshine that of his rivals, the Vivarini of Murano; he embodied, with ever growing and maturing power, all the devotional gravity and much also of the worldly 'splendour of the Venice of his time; and he saw his influence propagated by a host of pupils, two of whom at least, Giorgione and Titian, surpassed their master. Giorgione he outlived by five years; Titian, as we have seen, challenged an equal place beside his teacher. Among the best known of his other pupils were, in his earlier time, Andrea Previtali, Cima da Conegliano, Marco Basaiti, Niccolo Rondinelli, Piermaria Pennacchi, Martino da Udine, Girolamo Mocetto; in later time, Pierfrancesco Bissolo, Vincenzo Catena, Lorenzo Lotto and Sebastian del Piombo.

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BIBLIOGRAPHY.-Vasari, ed. Milanesi, vol. iii.; Ridolfi, Le Maraviglie, &c., vol. i.; Francesco Sansovino, Venezia Descritta: Morelli, Notizia, &c., de un Anonimo; Zanetti, Pittura Veneziana: F. Aglietti, Elogio Storico di Jacopo e Giovanni Bellini; G. Berna sconi, Cenni intorno la vita e le opere di Jacopo Bellini: Moschini. Giovanni Bellini e pittori contemporanei: E. Galichon in Gazelle des beaux-arts (1866); Crowe and Cavalcaselle, History of Painting in North Italy, vol. i.; Hubert Janitschek, Giovanni Bellini Dohme's Kunst und Künstler; Julius Meyer in Meyer's Allgemernes Künstler-Lexikon, vol. ii. (1885); Pompeo Molmenti, "I pittori Bellini" in Studi e ricerche di Storia d'Arte; P. Paoletti. Raccolta di documenti inediti, fasc. i. Vasari, Vite di Gentile da Fabriano e Villor Pisanello, ed. Venturi; Corrado Ricci in Rassegna d' Arte (1901, 1903), and Rivista d' Arte (1906); Roger Fry, Giovanni Bellini in The Artist's Library"; Everard Meynell, Giovanni Bellini in Newnes's "Art Library" (useful for a nearly complete of reproductions of the known paintings): Corrado Ricci, Jacopo Bellini ei suoi Libri di Disegni; Victor Goloubeff, Les Dessins de Jacopo Bellini (the two works last cited reproduce in full, that of M. Goloubeff by far the most skilfully, the contents of both the Paris and the London sketch-books). (S. C.)

renum, 1662), he was chosen professor of theoretical medicine at Pisa, but soon after was transferred to the chair of anatomy. After spending thirty years at Pisa, he was invited to Florence and appointed physician to the grand duke Cosimo III., and was also made senior consulting physician to Pope Clement XI. He died at Florence on the 8th of January 1704. His works were published in a collected form at Venice in 1708.

BELLINI, VINCENZO (1801-1835), operatic composer of the Italian school, was born at Catania in Sicily, on the 1st of November 1801. He was descended from a family of musicians, both his father and grandfather having been composers of some reputation. After having received his preparatory musical education at home, he entered the conservatoire of Naples, where he studied singing and composition under Tritto and Zingarelli. He soon began to write pieces for various instruments, as well as a cantata and several masses and other sacred compositions. His first opera, Adelson e Savina, was performed in 1825 at a small theatre in Naples; his second dramatic work, Bianca e Fernando, was produced next year at the San Carlo theatre of the same city, and made his name known in Italy. His next work, Il Pirata (1827), was written for the Scala in Milan, to words by Felice Romano, with whom Bellini formed a union of friendship to be severed only by his death. The splendid rendering of the music by Tamburini, Rubini and other great Italian singers contributed greatly to the success of the work, which at once established the European reputation of its composer. In almost every year of the short remainder of his life he produced a new operatic work, which was received with rapture by the audiences of France, Italy, Germany and England. The names and dates of four of Bellini's operas familiar to most lovers of Italian music are: I Montecchi e Capuleti (1830), in which the part of Romeo became a favourite with all the great contraltos; La Sonnambula (1831); Norma, Bellini's best and most popular creation (1831), and 1 Puritani (1835), written fu the Italian opera in Paris, and to some extent under the influence of French music. In 1833 Bellini had left his country to accom. pany to England the singer Pasta, who had created the part of his Sonnambula. In 1834 he accepted an invitation to write an opera for the national grand opera in Paris. While he was carefully studying the French language and the cadence of French verse for the purpose, he was seized with a sudden illness and died at his villa in Puteaux near Paris on the 24th of September 1835. His operatic creations are throughout replete with a spirit of gentle melancholy, frequently monotonous and almost always undramatic, but at the same time irresistibly sweet To this spirit, combined with a rich flow of cantilena, Bellini's operas owe their popularity "I shall never forget," wrote Wagner, "the impression made upon me by an opera of Bellini at a period when I was completely exhausted with the everlastingly abstract complication used in our orchestras, when a simple and noble melody was revealed anew to me."

See also G. Labat, Bellini (Bordeaux, 1865); A. Pougin, Bellini, sa vie et ses œuvres (Paris, 1868).

BELLINZONA (Ger. Bellenz), the political capital of the Swiss canton of Tessin or Ticino. It is 105 m. from Lucerne by the St Gotthard railway, 19 m. from Lugano and 14 m. from Locarno at the head of the Lago Maggiore, these two towns having been till 1881 capitals of the canton jointly with Bellin; zona. The old town is built on some hills, on the left bank of the Tessin or Ticino river, and a little below the junction of the main Ticino valley (the Val Leventina) with that of Mesocco. It thus blocked the road from Germany to Italy, while a great wall was built from the town to the river bank. Bellinzona still possesses three picturesque castles (restored in modern times). dating in their present form from the 15th century They belonged for several centuries to the three Swiss cantons which were masters of the town. The most westerly, Castello Grande BELLINI, LORENZO (1643-1704), Italian physician and or of San Michele, belonged to Uri; the central castle, that of anatomist, was born at Florence on the 3rd of September 1643. Montebello, was the property of Schwyz; while the most At the age of twenty, when he had already begun his researches easterly castle, that of Sasso Corbaro, was in the hands of Unteron the structure of the kidneys and had described the ducts walden. The 13th-century church of San Biagio (Blaise) has a known by his name (Exercitatio anatomica de structura et ušu | remarkable 14th-century fresco, while the collegiate church of

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San Stefano dates from the 16th century in 1900 the population | BELLO, ANDRÉS (1781-1865), South American poet and of Bellinzona was 4949, practically all Romanists and Italian-scholar, was born at Caracas (Venezuela) on the 29th of November speaking

1781, and in early youth held a minor post in the civil administra. Possibly Bellinzona is of Roman origin, but it is first mentioned tion. He joined the colonial revolutionary party, and in 1810 in 590. It played a considerable part in the early history of was sent on a political mission to London, where he resided for Lombardy, being a key to several Alpine passes. In the 8th nineteen years, acting as secretary to the legations of Chile, century it belonged to the bishop of Como, while in the 13th and Colombia and Venezuela, studying in the British Museum, 14th centuries it was tossed to and fro between the cities of Milan supplementing his small salary by giving private lessons in and Como. In 1402 it was taken from Milan by Albert von Sax, Spanish, by journalistic work and by copying Jeremy Bentham's lord of the Val Mesocco, who in 1419 sold it to Uri and Obwalden, almost indecipherable manuscripts. In 1829 he accepted a which, however, lost it to Milan in 1422 after the battle of Arbedo. post in the Chilean treasury, settled at Santiago and took a In 1499 (like the rest of the Milanese) it was occupied by the prominent part in founding the national university (1843), of French, but in 1500 it was taken by Uri. In 1503 the French king which he became rector. He was nominated senator, and died ceded it to Uri, Schwyz and Unterwalden, which henceforth at Santiago de Chile on the 15th of October 1865. Bello was ruled it very harshly through their bailiffs till 1798. At that mainly responsible for the civil code promulgated on the 14th date it became the capital of the canton Bellinzona of the of December 1855. His prose works deal with such various Helvetic republic, but in 1803 it was united to the newly-formed subjects as law, philosophy, literary criticism and philology; canton of Tessin.

(W. A. B. C) of these the most important is his Gramática castellana (1847), BELLMAN, KARL MIKAEL (1740-1795), Swedish poet, son the leading authority on the subject. But his position in literaof a civil servant, was born at Stockholm on the 4th of February ture proper is secured by his Silvas Americanas, a poem written 1740. When quite a child he developed an extraordinary gift during his residence in England, which conveys with extraof improvising verse, during the delirium of a severe illness, ordinary force the majestic impression of the South American weaving wild thoughts together lyrically and singing airs of his landscape. own composition. When he was nincteen he became clerk in Bello's complete works were issued in fifteen volumes by the a bank and afterwards in the customs, but his habits wereject of an excellent biography (Santiago de Chile, 1882) by Miguel

Chilean government (Santiago de Chile, 1881-1893): he is the subirregular and he was frequently in great distress, particularly Luis Amunátegui.

UF-K) after the death of his patron, Gustavus III. As early as 1757 he published Evangeliske Dödstankar, meditations on

BELLO-HORIZONTE, or MInAs, a city of Brazil, capital of Passion from the German of David von Schweidnitz, and during the state of Minas Geraes since 1898, about 50 m. N.W. of the next few years wrote, besides other translations, a great Ouro Preto, connected with the Central of Brazil railway by a quantity of poems, imitative for the most part of Dalin. In branch line 9 m. in length. Pop. (estimated) in 1906, 25,000 to 1760 appeared his first characteristic work, Månan (The Moon), 30,000. The city was built by the state on an open plateau,

and a satirical poem, which was revised and edited by Dalin. But provided with all necessary public buildings, gas, water and the great work of his life occupied him from 1765 to 1780, and tramway services before the seat of government was transferred consists of the collections of dithyrambic odes known as Pred- from Ouro Preto. The cost of transfer was about £1,000,000. mans Epistlar (1790) and Fredmans Sånger (1791) Fredman The city has grown rapidly, and is considered one of the most and his friends were well-known characters in the Stockholm attractive state capitals of Brazil pot-houses, where Bellman had studied them from the life

BELLONA (originally DUELLONA), in Roman mythology, No poetry can possibly smell less of the lamp than Bellman's. the goddess of war (bellum, i.e. duellum), corresponding to the He was accustomed, when in the presence of none but con-Greek Enyo. By later mythologists she is called sometimes fidential friends, to announce that the god was about to visit the sister, daughter or wife of Mars, sometimes his charioteer him. He would shut his eyes, take his zither, and begin appar

or nurse. Her worship appears to have been promoted in Rome ently to improvise the music and the words of a long Bacchic chiefly

by the family of the Claudii, whose Sabine origin, together ode in praise of love or wine. Most of his melodies are taken with their use of the name of " Nero," has suggested an identifdirect, or with slight adaptations, from old Swedish ballads, and cation of Bellona with the Sabine war goddess Nerio, herself still retain their popularity. Fredman's Epistles bear the clear identified, like Bellona, with Virtus. Her temple at Rome, impress of individual genius; his torrents of rhymes are not dedicated by Appius Claudius Caecus (296 B.c.) during a battle without their method; wild as they seem, they all conform to with the Samnites and Etruscans (

Ovid, Fasti vi. 201), stood in the rules of style, and among those that have been preserved the Campus Martius, near the Flaminian Circus, and outside there are few that are not perfect in form. A great Swedish the gates of the city. It was there that the senate met to discuss critic has remarked that the voluptuous joviality and the humour a general's claim to a triumph, and to receive ambassadors of Bellman is, after all, only " sorrow clad in rose-colour," and from foreign states. In front of it was the columna bellica, this underlying pathos gives his poems their undying charm. where the ceremony of declaring war by the fetialis was performed His later works, Bacchi Tempel (The Temple of Bacchus) (1783), From this native Italian goddess is to be distinguished the eight numbers of a journal called Hvad behagas? (What you Asiatic Bellona, whose worship was introduced into Rome from Will

) (1781), in 1780 a religious anthology entitled in a later Comana, in Cappadocia, apparently by Sulla, to whom she had edition (1787) Zions Högtid (Zion's Holiday), and a translation appeared, urging him to march to Rome and bathe in the blood of Gellert's Fables, are comparatively unimportant. He died of his enemies (Plutarch, Sulla, 9). For her a new temple was on the 11th of February 1795. Much of Bellman's work was her fanatical rites, the prominent feature of which was to lacerate

built, and a college of priests (Bellonarii) instituted to conduct only printed after his death, Bihang till Fredmans. Epistlar themselves and sprinkle the blood on the spectators (Tibullus (Nyköping, 1809), Fredmans Handskrifter (Upsala, 1813), Skaldestycken (" Pocms,” Stockholm, 1814) being among the i. 6. 45-50). To make the scene more grim they wore black most important of these posthumous works. A colossal bronze dresses (Tertullian, De Pallio) from

head to foot. The festival bust of the poet by Byström (erected by the Swedish Academy of Bellona, which originally took place on the 3rd of June, was in 1829) adorns the public gardens of Stockholm, and a statue altered to the 24th of March, after the confusion of the Roman by Alfred Nyström is in the Hasselbacken, Stockholm. Bellman Bellona with her Asiatic namesake. had a grand manner, a fine voice and great gifts of mimicry,

See Tiesler, De Bellonae Cultu (1842). and was a favourite companion of King Gustavus III.

BELLOT, JOSEPH RENÉ (1826–1853), French Arctic explorer, The best edition of his works was published at Stockholm, edited farrier. With the aid of the authorities of his native town he

was born at Rochefort on the 18th of March 1826, the son of a s vols., 1856-1861): see also monographs on Bellman by Nils was enabled at the age of fifteen to enter the naval school, in Erdmann (Stockholm, 1895) and by F. Niedner (Berlin, 1905). which he studied two years and earned a high reputation Be

then took part in the Anglo-French expedition of 1845 to Mada- | place to another. Formerly all such artificially-produced gascar, and received the cross of the Legion of Honour for currents of air were used to assist the combustion of fires and distinguished conduct. He afterwards took part in another furnaces, but now this purpose only forms a part of the uses to Anglo-French expedition, that of Parana, which opened the which they are put. Blowing appliances, among which are river La Plata to commerce. In 1851 he joined the Arctic included bellows, rotary fans, blowing engines, rotary blowers expedition under the command of Captain Kennedy in search and steam-jet blowers, are now also employed for forcing pure of Sir John Franklin, and discovered the strait between Boothia air into buildings and mines for purposes of ventilation, for Felix and Somerset Land which bears his name. Early in 1852 withdrawing vitiated air for the same reason, and for supplying he was promoted lieutenant, and in the same year accompanied the air or other gas which is required in some chemical processes. the Franklin search expedition under Captain Inglefield. As on Appliances of this kind differ from air compressors in that they the previous occasion, his intelligence, devotion to duty and are primarily intended for the transfer of quantities of air at low courage won him the esteem and admiration of all with whom he pressures, very little above that of the atmosphere, whereas the was associated. While making a perilous journey with two latter are used for supplying air which has previously been comrades for the purpose of communicating with Sir Edward raised to a pressure which may be many times that of the atmoBelcher, he suddenly disappeared in an opening between the sphere (see POWER TRANSMISSION: Pneumatic). broken masses of ice (August 1853). A pension was granted to his family by the emperor Napoleon III., and an obelisk was erected to his memory in front of Greenwich hospital.

Among the earliest contrivances employed for producing the movement of air under a small pressure were those used in Egypt during the Greek occupation. These depended upon the heating of the air, which, being raised in pressure and bulk, was made to force water out of closed vessels, the water being afterwards employed for moving some kind of mechanism. In the process of iron smelting there is still used in some parts of India an artificial blast, produced by a simple form of bellows made from the skins of goats; bellows of this kind probably represent one of the earliest contrivances used for producing currents of air.

The bellows' now in use consists, in its simplest form, of two flat boards, of rectangular, circular or pear shape, connected round their edges by a wide band of leather so as to include an air chamber, which can be increased or diminished in volume by

leather is kept from collapsing, on the separation of the boards, by several rings of wire which act like the ribs of animals. The lower board has a hole in the centre, covered inside by a leather flap or valve which can only open inwards; there is also an open outlet, generally in the form of a pipe or nozzle, whose aperture is much smaller than that of the valve. When the upper board is raised air rushes into the cavity through the valve to fill up the partial vacuum produced; on again depressing the upper board the valve is closed by the air attempting to rush out again, and this air is discharged through the open nozzle with a velocity depending on the pressure exerted.

BELLOWS, ALBERT F. (1829-1883), American landscapepainter, was born at Milford, Massachusetts, on the 20th of November 1829. He first studied architecture, then turned to painting, and worked in Paris and in the Royal Academy at Antwerp. He painted much in England; was a member of the National Academy of Design, and of the American Water Color Society, New York; and an honorary member of the Royal Belgian Society of Water-Colourists. His earlier work was genre, in oils; after 1865 he used water-colours more and more exclusively and painted landscapes. Among his water-colours are "Afternoon in Surrey" (1868); "Sunday in Devonshire " (1876), exhibited at the Philadelphia Exposition; "New Eng-separating the boards or bringing them nearer together. The land Village School " (1878); and " The Parsonage " (1879). He died in Auburndale, Massachusetts, on the 24th of November 1883. BELLOWS, HENRY WHITNEY (1814-1882), American clergyman, was born in Boston, Massachusetts, on the 11th of June 1814. He graduated at Harvard College in 1832, and at the Harvard Divinity School in 1837, held a brief pastorate (1837-1838) at Mobile, Alabama, and in 1839 became pastor of the First Congregational (Unitarian) church in New York City (afterwards All Souls church), in charge of which he remained until his death. Here Bellows acquired a high reputation as a pulpit orator and lyceum lecturer, and was a recognized leader in the Unitarian Church in America. For many years after 1846 he edited The Christian Inquirer, a Unitarian weekly paper, and he was also for some time an editor of The Christian Examiner. In 1857 he delivered a series of lectures in the Lowell Institute course, on "The Treatment of Social Diseases." At the outbreak of the Civil War he planned the United States Sanitary Commission, of which he was the first and only president (1861 to 1878). He was the first president of the first Civil Service Reform Association organized in the United States (1877), was an organizer of the Union League Club and of the Century Association in New York City, and planned with his parishioner and friend, Peter Cooper, the establishment of Cooper Union. In 1865 he proposed and organized the national conference of Unitarian and other Christian churches, and from 1865 to 1880 was chairman of its council. He died in New York City on the 30th of January 1882. A bronze memorial tablet by Augustus Saint Gaudens was unveiled in All Souls church in 1886. His published writings include Restatements of Christian Doctrine in Twenty-Five Sermons (1860); Unconditioned Loyalty (1863), a strong pro-Union sermon, which was widely circulated during the Civil War; The Old World in its New Face: Impressions of Europe in 1867-1868 (2 vols., 1868-1869); Historical Sketch of the Union League Club (1879); and Twenty-Four Sermons in All Souls Church, New York, 1865-1881 (1886).

See Russell N. Bellows, Henry Whitney Bellows (Keene, N.H., 1897), a biographical sketch reprinted from T. B. Peck's Bellows Family Genealogy: John White Chadwick, Henry W. Bellows: His Life and Character (New York, 1882), a memorial address; and Charles J. Stillé, History of the United States Sanitary Commission (Philadelphia, 1866).

BELLOWS and BLOWING MACHINES, appliances used for producing currents of air, or for moving volumes of air from one

The current of air produced is evidently not continuous but intermittent or in puffs, because an interval is needed to refill the cavity after each discharge. In order to remedy this drawback the double bellows are used. To understand their action it is only necessary to conceive an additional board with valve, like the lower board of the single bellows, attached in the same way by leather below this lower board. Thus there are three boards, forming two cavities, the two lower boards being fitted with air-valves. The lowest board is held down by a weight and another weight rests on the top board. In working these double bellows the lowest board is raised, and drives the air from the lower cavity into the upper. On lowering the bottom board again a fresh supply of air is drawn in through the bottom valve, to be again discharged when the board is raised. As the air passes from the lower to the upper cavity it is prevented from returning by the valve in the middle board, and in this way a quantity of air is sent into the upper cavity each time the lowest board is raised. The weight on the top board provides the necessary pressure for the blast, and at the same time causes the current of air delivered to be fairly continuous. When the air is being forced into the upper cavity the weight is being 1 The Old English word for this appliance was blástbaelig, i.e. "blow-bag," cf. German Blasebalg. By the 11th century the first part of the word apparently dropped out of use, and baelig, bylig, bag, is found in early glossaries as the equivalent of the Latin follis. Baelig became in Middle English bely, i.e. "belly," a sack or bag, and so the general word for the lower part of the trunk in man and animals, the stomach, and another form, probably northern in origin, belu, belw, became the regular word for the appliance, the plural" "bellies "being still used till the 16th century, when "bellows appears, and the word in the singular ceases to be used. The verb "to bellow" of the roar of a bull, or the low of a cow, is from Old English bellan, to bell, roar.

ing, the weight is slowly forcing the top board down and thus keeping up the flow of air.

raised, and, during the interval when the lowest board is descend-blowing engines are used require the air to be above the pressure of the outer atmosphere. This means that the discharge valves do not open quite at the beginning of the delivery stroke, but remain closed until the air in the cylinder has been reduced in volume and so increased in pressure to that of the air in the discharge chamber.

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Hand-bellows for domestic use are generally shaped like a pear, with the hinge at the narrow end. The same shape was adopted for the older forms of smiths' bellows, with the difference that two bellows were used superposed, in a manner similar to that just described, so as to provide for a continuous blast. In the later form of smiths' bellows the same principle is employed, but the boards are made circular in shape and are always maintained roughly parallel to one another. These are shown on figs. 1 and 2. Here A is the blast pipe, B the movable lowest board, C the fixed -omin dito ad exit vnani middle board, T close to which the pipe A is Linserted, and D Dis the movable Wuppermost board pressed upon by 30the weight shown. The board B is raised by means of a hand lever L, #through either a chain or a connecting rod, and lowered by a FIGS. I and 2.-Common Smiths' Bell Bellows. weight. The size of the weight on D depends on the air pressure required. For instance, if a blast pressure of half a pound per square inch is wanted and the boards are 18 in. in diameter, and therefore have an area of 254 sq. in., on each of the 254 sq. in. there is to be a pressure of half a pound, so that the weight to balance this must be half multiplied by 254, or 127 lb. The diameter of the air-pipe can be varied to suit the required conditions. Instead of bellows with flexible sides, a sliding arrangement is sometimes used; this consists of what are really two boxes fitting into one another with the open sides both facing inwards, as if one were acting as a lid to the other. By having a valve and outlet pipe fitted as in the bellows and sliding them alternately apart and together, an intermittent blast is produced. The chief defect of this arrangement is the leakage of air caused by the difficulty in making the joint a sufficiently good fit to be air-tight.

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Blowing Engines.-Where larger quantities of air at higher pressufes than can conveniently be supplied by bellows are required, as for blast furnaces and the Bessemer process of steelmaking, what are termed "blowing engines" are used. The mode of action of a blowing engine is simple. When a piston, accurately fitting a cylinder which has one end closed, is forcibly moved towards the other end, a partial vacuum is formed between the piston and the blank end, and if this space be allowed to communicate with the outer atmosphere air will flow in to fill the vacuum. When the piston has completed its movement or "stroke," the cylinder will have been filled with air. On the return of the piston, if the valve through which the air entered is now closed and a second one communicating with a chamber or pipe is opened, the air in the cylinder is expelled through this second valve. The action is similar to that of the bellows, but is carried out in a machine which is much better able to resist higher pressures and which is more convenient for dealing with large quantities of air. The valves through which the atmosphere or "free" air is admitted are called "admission" or "suction" valves, and those through which the air is driven from the cylinder are the "discharge" "delivery" valves. Formerly one side only of the blowing piston was used, the engine working "single-acting "; but now both sides of the piston are utilized, so that when it is moving in either direction suction will be taking place on one side and delivery on the other. All processes in connexion with which

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The power used to actuate these blowing-engines is in most cases steam, the steam cylinder being placed in line or " tandem" with the air cylinder, so that the steam piston rod is continuous with or directly joined to the piston rod of the air cylinder. This plan is always adopted where the cylinders are placed horizontally, and often in the case of vertical engines. The engines are generally built in pairs, with two blowing cylinders and one high-pressure and one low-pressure steam cylinder, the piston rods terminating in connecting rods which are attached to the pins of the two cranks on the shaft. In the centre of this shaft, midway between the two engines, there is usually placed a heavy flywheel which helps to maintain a uniform speed of turning. Some of the largest blowing engines built in Great Britain are arranged as beam engines; that is to say, there is a heavy rocking beam of cast iron which in its middle position is horizontal. One end of this beam is linked by a short connecting rod to the end of the piston rod of the blowing cylinder, while the other end is similarly linked to the top of the steam piston rod, so that as the steam piston comes up the air piston goes down and vice versa. At the steam end of the beam a third connecting rod works the crank of a flywheel shaft,

About the end of the 19th century an important development took place which consisted in using the waste gas from blast furnaces to form with air an explosive mixture, and employing this mixture to drive the piston of the actuating cylinder in precisely the same manner as the explosive mixture of coal gas and air is used in a gas engine. Since the majority of blowing engines are used for providing the air required in iron blast furnaces, considerable saving should be effected in this way, because the gas which escapes from the top of the furnace is a waste product and costs nothing to produce.

The general action of a blowing engine may be illustrated by the sectional view shown on fig. 3, which represents the

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FIG. 3.-Section of Cylinder of Early Blowing Engine (1851). internal view of one of the blowing cylinders of the engines erected at the Dowlais Ironworks as far back as 1851. Many of the details are now obsolete, but the general scheme is the same as in all blowing engines. Here A is the air cylinder; in this is a piston whose rod is marked R; this piston is usually made air-tight by some form of packing fitted into the groove which runs round its edge. In this particular case the cylinder is placed vertically and its piston rod is actuated from the end of a rocking beam. The top and bottom ends are closed by covers and in these

are a number of openings controlled by valves opening inwards | and C, the low-pressure one, are placed in tandem with the air so that air can flow freely in but cannot return. The piston is shown moving downwards. Air is now being drawn into the space above the piston through the valves at the top, and the air in the space A below the piston, drawn in during the previous up-stroke, is being expelled through the valve into the discharge chamber B, thence passing to the outlet pipe O. The action is reversed on the up-stroke. Thus it will be seen that air is being delivered both during the up-stroke and the down-stroke, and therefore flows almost continuously to the furnaces. There must, however, be momentary pauses at the ends of the strokes when the direction of movement is changed, and as the piston, though worked from an evenly rotating crank shaft, moves more quickly at the middle and slows down to no speed at the ends of its travel, there must be a considerable variation in the speed of

FIG. 4-Vertical Section of Lackenby Blowing Engines (1871). delivery of the air. The air is therefore led from O into a large storage chamber or reservoir, whence it is again taken to the furnace; if this reservoir is made sufficiently large the elasticity of the air in it will serve to compensate for the irregularities, and a nearly uniform stream of air will flow from it. The valves used in this case and in most of the older blowing engines consist of rectangular metal plates hinged at one of the longer edges; these plates are faced with leather or indiarubber so as to allow them to come to rest quietly and without clatter and at the same time to make them air-tight. It will be seen that some of these valves hang vertically and others lie flat on the bottom of the cover. The Dowlais cylinder is very large, having a diameter of 1 ft. and a piston stroke of 12 ft., giving a discharge of 44,000 cub. ft. of air per minute, at a pressure of 44 lb to the square inch. A later design of blowing engine, built in 1871 for the Lackenby iron-works, Middlesbrough, is shown in section in fig 4. and is of a type which is still the most common, especially in the north of England. Here A, the high-pressure steam cylinder,

cylinders B, B, whose pistons they actuate. In these blowing cylinders the inlet valves in the bottom are circular disk valves of leather, eighteen in number; the inlet valves T on the top of the cylinder are arranged in ten rectangular boxes, having openings in their vertical sides, inside which are hung leather flap valves. The outlet valves O are ten in number at each end of the cylinders, and are hung against flat gratings which are arranged round the circumference. The blast is delivered into a wrought iron casing M which surrounds the cylinder. The combined area of the inlet valves is 860 sq. in., or one-sixth the area of the piston. The speed is twenty-four revolutions per minute and the air delivered at this speed is 15,072 cubic ft. per minute, the horse-power in the air cylinders being 258. The circulating pump E, air pump F, and feed pumps G. G, are worked off the cross-head on the low-pressure side.

A more modern form of blowing engine erected at the Dowlais works about the end of the 19th century, may be taken as typical of the present design of vertical blowing engine in use in Great Britain. The two air cylinders are placed below and in tandem with the steam cylinders as in the last case. The piston rods also terminate in connecting rods working on to the crank shaft. The air cylinders are each 88 in. in diameter, and the high and low pressure cylinders of the compound steam engine are 30 in. and 64 in. respectively, while the common stroke of all four is 60 in. The pressure of the air delivered varies from 49 to ro lb per sq. in. and the quantity per minute is 25,000 cub. ft. Each engine develops about 1200 horse-power. It is to be noted that flap valves such as those used in the 1851 Dowlais engine have in most cases given place to a larger number of circular steel disk valves, held to their seats by springs.

In a large blowing engine built in 1905 by Messrs Davy Bros. of Sheffield for the North-Eastern Steel Company at Middles brough (see Engineering, January 6, 1905) the same arrangement was adopted as in that just described. The two air cylinders are each go in. diameter and have a stroke of 72 in. The capacity of this engine is 52,000 cub. ft. of air per minute, delivered at a pressure of from 12 to 15 lb per sq. in. when running at a speed of thirty-three revolutions per minute. The air valves consist of a large number of steel disks resting on circular seatings and held down by springs, which for the delivery valves are so adjusted in strength that they lift and release the air when the desired working pressure has been reached. It is worthy of note that in this engine no attempt is made to make the air pistons air-tight in the usual way by having packing rings set in grooves round the edge, but the piston is made deeper than usual and turned so as to be a very good fit in the cylinder and one or two small grooves are cut round the edge to hold the lubricant.

To illustrate a blowing engine driven by a gas engine supplied with blast furnace gas, fig. 5 gives a diagrammatic view of the blowing cylinder of an engine built by Messrs Richardsons, Westgarth & Co. of Middlesbrough about 1905The gas cylinder is not shown. It will be seen that the air cylinder is horizontal, and it is arranged to work in tandem with the gas motor cylinder. The chief point of interest is to be found in the arrangement of the details of the air cylinder. Its diameter is 86 in. and the length of piston stroke 55 in. As to the arrangement of the valves, if the piston be moving in the direction shown, on the left side of the piston at A air is being discharged, and follows the course indicated by the arrows, so as first to pass into the annular chamber which forms a continuation of the

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