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; towards the year 1505, the portrait of the doge Loredauo in tho 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. '-l
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 1501-1504 the marchioness Isabella Gonzaga of Mantua had had great difficulty in obtaining delivery from him of a pictured tht " Madonna and Saints " (now lost) for which part payment had been made in advance. In 1505 she endeavoured through Cardinal Eembo 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 Dilrer, visiting Venice for a second lime 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 pictnrc of the " Preaching of St. Mark " which he had left unfinished; a task on the fulfilment of which the bequest by the elder brother lo 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 Titian's ,application was first granted, then after a year rescinded, and then after another year or two granted again; and the aged master must no doubt have undergone some annoyance from his sometime pupil's proceedings.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 Almvick.
Both in the artistic and in the worldly sense, the career of Giovanni Bellini was upon the whole the most serenely and unbrokcnly 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 Vivariui 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 hoit 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 Prcvitali. Cima da Concgliano, Marco Basaiti, Niccolo Rondinclli, Piermaria Pennacchi, Martino da Udine, Girolamo Mocctto; in later time, Picrfranccsco Bissolo, Vincenzo Catena, Lorenzo Lotto and Sebastian del Tiombo.
Bibliography.—Vaftari, cd- Milancal, vol. fii.; Riclolfi, te Afarariglie, &c.. vol. i.j Francesco Sansovino, Venetia Dtserilta; Morelli, Notifta, &f.t dt v» A no mm o; Zanectt, Pittura Venetiana; F. Ajjlictli, Etogto S/ot-kc di Jowpo t Giovanni Bellini'. G BernaBcoai, Cenni interne fa vita e le opere di Jccoffo Bellini; Moschini. Giovanni Bellini e f&tori conten-^oranci;^.. Galichon in Gazette des beaux-art* (1866); Crowe and Cavnlcaselle. History of Pointing in North Ituly, vol. i.; Hubert Jamtschefc, "Giovanni Bellini'7 in Dohme's Kvnst vnd Kunstlrr; Julius Meyer in Meyer's A'lge~ tttftne t Kunstler-Lexikon, vol. ui. (1885); Pompeo M ol men t i, "I pittori Bcflim" in Stwti e ricerche di Stona d* Arte; P. Paotctti, ffaccolta dt doeumenti inediti. fasc. i,; Vssari, Vite di Gentile da o * Vittcr Piiatttllo, ed. Venturi; Corrado Ricci in Ktu$egna
st-t of reproductions of the known paintfngs); Corra'cTo Ricci, Jncofw Bfllini 0 i tutfi L&>ri di Dire^ni; Victor Goloobeff. Les Dcssins de Jacnpo Bellini (the two works last died reproduce in full, that of M. Goloubcff by far the most skilfully, the contents of both the Paris and the London sketch-books). i (5. C)
BELLINI, LORENZO (1643-1704), Italian physldan and anntomiat, was born al Florence on the jrd of Scptenibcr 1643. At the age of twenty, when he had already begun his researches '0p the structure of the kidneys and had described the ducts known by his rume (BxercittUio anatomka dt structure et uitt
rfmrflf, 1662), he was chosen professor of theoretical medicine at Pisa, but soon after was transferred to the chair of anatomy. After spending thirty years at Pisa, he was invited to Florence and appointed physician to the grand duke Cosimo III., and was also made senior consulting physician to Pope Clement XI. He died at Florence on the 8th of January 1704. His works were published in a collected form at Venice in 1708.
BELLINI, VINCENZO (1,801-1835), operatic composer of the Italian school, was born at Catania in Sicily, on the ist of November 1801. He was descended from a family of musicians, both his father and grandfather having been composers of some reputation. After having received his preparatory musical education at home, he entered the conservatoire of Naples, where he studied singing and composition under Tritto and Zingarelli. He soon began to write pieces for various instrumen ts, as well as a cantata and several masses and other sacred compositions. His first opera, Addson e Sontia, was performed in 182$ at a small theatre in Naples; his second dramatic work, Bianco 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, II firata (1827), was written for the Scala in Milan, to words by Felice Romano, with whom Bellini formed n union of friendship to be severed only by his death. The splendid rendering of the music by Tamburtni, 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* 7 Montecchi e Capvtdi (1830), in which the part of Romeo became a favourite with al) the great contraltos; La Sonnambvla (1831); Nortna, Bellini's best and most popular creation (1831), and ] Puritani (1835), written to* the Italian opera in Paris, and to some extent under the influence of French music. In 1833 Bellini had left his country to accompany to England the singer Pasta, who had created the part ol his Sonnambult. 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 seucd with a sudden illness and died at his villa in Puteaux near Paris on the 24th of Sepicmbci 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 "1 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."
Sec aim G, Labat, Billini (Bordeaux, 1865); A. Pougin, /»'••• sa vie ct ses ausrcs U'aris, 1866).
BELLINZONA (Ger. Bellcnz), the political capital of the Swiss canton of Tessin or Ticino. It b 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 til) 1881 capitals of the canton jointly with BelUn: zona. Theold 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. Ii thus blocked the road from Germany lo Italy, while B great wall was built from the town to the river bank. Bellinzona stiU possesses three picturesque castles (restored in modern times), dating in thfcir present form from the J5th century They belonged for several centuries to the three Swiss cantons which were masters of the town. The most westerly, Casiello Grande or of San Michele, belonged to Uri; the central castle, that of Monti-hello, was the property of Schwyz; while the moM easterly castle, that of Sasso Corbaro, was in the hands of Untcrwaldcn. The 13th-century church of San Biagio (Blaise) has a remarkable 14th-century fresco, while the collegiate church ol San Stefano dates from the i6th century In 1900 the population of Bellinzona was 4949, practically all Romanists and Italianspeaking.
Possibly Bcllinzona is of Roman origin, but it Is first mentioned in 500. It played a considerable part in the early history of Lombardy, being a key to several Alpine passes. In the 8th century it belonged to the bishop of Como, while in the ijth and I4th centuries it was tossed to and fro between the cities of Milan and Como. In 1402 it was taken from Milan by Albert von Sax, lord of the Val Mcsocco, who in 1419 sold it to Uri and Obwalden, which, however, lost'it to Milan in 1412 after the battle of Arbedo. In 1499 (like the rest of the Milanese) it was occupied by the rrnii li.lmt in 15'joit was taken by I'ri. In 1503 the French king ceded it to Uri, Schwyz and Untcrwaldcn, which henceforth ruled it very harshly through their bailiffs till 1798. At that date it became the capital of the canton Bcllinzona of the Helvetic republic, but in 1803 it was united to the newly-formed canton of Tcssin. (W. A. B. C )
BELLMAN. KARL MIKAEL (1740-1795), Swedish poet, son • •( a civil servant, was born at Stockholm on the 4th of February 1740. When quite a child he developed an extraordinary gift of improvising verse, during the delirium of a severe illness, weaving wild thoughts together lyrically and singing airs of his own composition. When he was nineteen he became clerk in a bank and afterwards in the customs, but his habits were irregular and he was frequently in great distress, particularly after the death of his patron, Gustavus III. As early as 1757 he published Evangeliska Dodstankar, meditations on the Passion from the German of David von Schweidnitz, and during the next few yean wrote, besides other translations, a great quantity of poems, imitative for the most part of Dalin. In 1760 appeared his first characteristic work, U&aan (The Moon), a satirical poem, which was revised and edited by Dalin. But the great work of his life occupied him from 1765 to 1780, and consists of the collections of dithyrambic odes known as Fredmans Epistlar (1700) and Fredmans Sanger (1791) Fredman and his friends were well-known characters in the Stockholm pot-houses, where Bellman had studied them from the life No poetry can possibly smell less of the lamp than Bellman's. He was accustomed, when in the presence of none but confidential friends, to announce that the god was about to visit htm. He would shut his eyes, take his zither, and begin apparently to improvise the music and the words of a long Bacchic ode in praise of love or wine. Most of his melodies arc taken direct, or with slight adaptations, from old Swedish ballads, and still retain their popularity. Fredman's Epistles bear the clear impress of individual genius; his torrents of rhymes arc not without their method; wild as they seem, they all conform to the rules of style, and among those that have been preserved there are few that are not perfect in form. A great Swedish critic has remarked that the voluptuous joviality and the humour of Bellman is, after all, only " sorrow clad in rose-colour," and this underlying pathos gives his poems their undying charm. His later works, Baccti Tempd (The Temple of Bacchus) (1783), eight numbers of a journal called Hwd bcliagasf (What you Will) (1781), in 1780 a religious anthology entitled in a later edition (1787) Zions Hogtid (Zion's Holiday), and a translation of Gellert's Fables, are comparatively unimportant. He died on the nth of February 1795. Much of Bellman's work was only printed after his death, Bikang till Fredmans Epistlar (Ntfkoping, 1809), Fredmans Handltrifler (Upsala, 1813), Skaldestycken (" Poems," Stockholm, 1814) being among the most important of these posthumous works. A colossal bronze bust of the poet by Bystrom (erected by Ox Swedish Academy in 1829) adorns the public gardens of Stockholm, and a statue by Alfred Nystrom is in the Hasselbacken, Stockholm. Bellman had a grand manner, a fine voice and great gifts of mimicry, and was a favourite companion of King Gustavus III.
The best edition of his works was published at Stockholm, edited by J. G. Carlen, with biographical notes, illustrations and music (5 veils.. 1856-1861); see also monographs on Bellman by Nils Erdmann (Stockholm, l695)andby F. Niedncr (Berlin, 1905).
BELLO. AMDRfe (1781-1805), South American poet aad scholar, was born at Caracas (Venezuela) on the 29th of No member 1781,and in early youth held a minor post in the civil administration. He joined the colonial revolutionary party, and la 1810 was sent on a political mission to London, where he resided for nineteen years, acting as secretary to the legations of Chile, Colombia and Venezuela, studying in the British Museum, supplementing his small salary by giving private lessons in Spanish, by journalistic work and by copying Jeremy Bentham's almost indecipherable manuscripts. In 1819 he accepted a post in the Chilean treasury, settled at Santiago and took a prominent part in founding the national university (1843), of which he became rector. He was nominated senator, and died at Santiago de Chile on the isth of October 1865. Bcllo was mainly responsible for the civil code promulgated on the uth of December 1855. His prose works deal with such various subjects as law, philosophy, literary criticism and philology; of these the most important is his Grarmliiia casltUana (1847), the leading authority on the subject. But his position in literature proper is secured by his Silvat A merit anas, a poem written during his residence in England, which conveys with extra— ordinary force the majestic impression of the South American landscape.
Bcllo'ft complete works were Issued in fifteen volumes by the Chilean government (Santiago dc Chile, 1881-1893): he is the subject of an excellent biography (Santiago de Chile, 1882) by Miguel Luis Amunaiegui. (J. F.-K-)
BELLO-HORIZONTE. or MiNAS, a city of Brazil, capital of the slate of Minas Geracs since 1898, about 50 m. N.W. of Ouro Prcto, connected with the Central of Brazil railway by a branch line 9 m. in length. Pop. (estimated) in 1906, 25,000 to 30,000. The city was built by the slate on an open plateau, and provided with all necessary public buildings, gas, water and tramway services before the scat of government was transferred from Ouro Prelo. The cost of transfer was about £1,000.coo. The city has grown rapidly, and is considered one of the most allractive slalc capitals of Brazil
BELLONA (originally Duellona), in Roman mythology, the goddess of war (brllum, i.e. ducllum), corresponding to the Greek Enyo. By later mythologisls she is called sometimes the sister, daughter or wife of Mars, sometimes his charioteer or nurse. Her worship appears to have been promoted in Rome chiefly by the family of Ihe Claudii, whose Sabine origin, together with ihcir use of the name of " Nero," has suggested an identification of Bellona with the Sabine war goddess Nerio, herself identified, like Bellona, with Virtus. Her temple at Rome, dedicated by Appius Claudius Caccus (296 B.C.) during a battle wkh the Samnites and Etruscans (Ovid, Fasti vi. 201), stood in the Campus Marlius, near the Flaminian Circus, and outside the gates of the city. It was there that the senate met to discus? a general's claim to a triumph, and to receive ambassador* from foreign states. In front of it was the columna brlluo. where the ceremony of declaring war by the f etialis was performed From this native Italian goddess is to be distinguished the Asiatic Bellona, whose worship was introduced into Rome from Comana, in Cappadocia, apparently by Sulla, to whom she had appeared, urging him to march to Rome and bathe in the blood of his enemies (Plutarch, Sulla. 9). For her a new temple was built, and a college of priests (Bdlonorii) instituted to conduct her fanatical rites, the prominent feature of which was to lacerate themselves and sprinkle the blood on the spectators (Tibullus i. 6. 45-50). To make the scene more grim they wore black dresses (Tertullian, De Pallia) from head to foot The festival of Bellona, which originally took place on the 3rd of June, waa altered to the 24th of March, after the confusion of the Roman Bellona with her Asiatic namesake.
Sec Ticslcr, Dt BeOmat Cultu (1842).
BELLOT. JOSEPH RENE (1826-1853), French Arctic explorer. was born at Rochefort on the i8th of March i8a6, the sou o! • farrier. With the aid of the authorities of his native town be was enabled at the age of fifteen to enter the naval school, in which he studied two years and earned a high reputation. :.. then took part in the Anglo-French expedition of 1845 to Madagascar, and received tbo cross of the Legion of Honour for distinguished conduct, lie afterwards took part in another Anglo-French expedition, that of Parana, which opened the river La Plata to commerce. In i8$i he joined the Arctic expedition under the command of Captain Kennedy in search ol Sir John Franklin, and discovered the strait between Boothia Felii and Somerset Land which bears his name. Early in iS•,-• he was promoted lieutenant, and in the same year accompanied the Franklin search expedition under Captain Inglelidd. As on the previous occasion, his intelligence, devotion to duty and courage won him the esteem and admiration of all with whom he was associated.' While making a perilous journey with two comrades for the purpose of communicating with Sir Edward Belcher, he suddenly disappeared in an opening between the 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.
BELLOWS, ALBERT F. (iSjo-iS8j), American landscapepainter, was born at Milford, Massachusetts, on the aoth of November i8?g. He rirst 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, ^Tew York; and an honorary member of the Royal Belgian Society of Watcr-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 arc " Afternoon in Surrey " (1868); " Sunday in Devonshire" (1876), exhibited at the Philadelphia Exposition; "New England Village School " (iS;8); and " The Parsonage " (1879). He died in Auburndale,Massachusetts, on the >4th of November 1883.
BELLOWS. HENRY WHITNEY (1814-188]), American clergyman, was born in Boston, Massachusetts, on the nth of June 1814. He graduated at Harvard College in 1832, and at the Harvard Divinity School in 1837, held a brief, pastorale (1837-1838) at Mobile, Alabama, and in 1839 became paslor of tbc 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 Tin 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 tbc 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 tbc Union League Club and of the Century Association in New York City, and planned with his parishioner and friend, Peter Cooper, (he establishment of Cooper Union. In 1865 he proposed and organized the national conference of . Unitarian and other ChrfctLn churches, and from 1865 to 1880 was chairman of its council, He died in New York City on the .;oth of January 1882. A bronze memorial tablet by Augustus Saint Gaudcns was unveiled in All Souls church in 1886. His published writings include Rtstalemtnts of Christian Doctrine in Tmnty-Pm Sermons (1860); Unconditioned Loyalty (1863), a strong pro-Union sermon, which was widely circulated during the Civil War; The Old World in in Nat Fact: Impression} ef Europe in iS6-?-iS6S (j vols., 1868-1869); Historical Sketch of the Union League Club (1879); *&& Twtnly-Ffttr Sermons in All Souls Church, flea York, iS6f.-i88i (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: Jfis Life And Cbamctrr (New York, iSbjl, a memorial address: and Charles J. Stillc, History of Iht United States Sanitary Commission (Philadelphia, 1866).
BELLOWS and BLOWING MACHINES, appliances used for producing currents of tir, or for moving volumes of air from one
place to another. Formerly all such artificially-produced currents of air were used to assist the combustion of fires and furnaces, but now this purpose only forms a part of the uses to which they are put. Blowing appliances, among which are included bellows, rotary fans, blowing engines, rotary blowers and steam-jet blowers, are now also employed for forcing pure air into buildings and mines for purposes of ventilation, for withdrawing vitiated air for the same reason, and for supplying the air or other gas which is required in some chemical processes. Appliances of this kind differ from air compressors in that they are primarily intended for the transfer of quantities of air at low pressures, very little above that of the atmosphere, whereas the latter arc used for supplying air which has previously been raised to a pressure which may be many times that of the atmosphere (see Powes Transmission: Pneumatic).
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; bellowi of this kind probably represent onr of the earliest contrivances used for producing currents of air..
The btllova1 now in use consists, in its simplest form, of two Sat 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 separating the boards or bringing them nearer together. The 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.
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 tbc 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 blastbaelig, i.t. "blow-bag," cf. German Blaseoalg. By the nth century the first part of the word apparently dropped out of use, and baelie. oyl'e, bag, is found in early glossaries as the equivalent of the Latin follis. Baelif became in Middle English '•-/•.•. i.e. " belly," a sack or bag. aad so the general word for the lower part of the trunk in man and animals, the stomach, and another form, probably northern in origin, bflu, belie, became the regular word for the appliance, the plural " bellies " being still used tillthe l6th century, when "bellows" appear*, and the word in the singular ceases to be used. The verb "to txjlow " of lie roar of a buB, or the low of a cow, is fiwm Old Mian, to bell, roar.
raised, and, during the interval when the lowest board is descending, the weight is slowly forcing the top board down and thus keeping up the flow of air.
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 Wast. In the later form of smiths' bellows the same principle is employed, but the boards arc made circular in shape and are always maintained roughly parallel to one another. These are shown on 6gs. 1 and 2. Here A U the blast pipe, B the movable lowest board,
C the fixed middle board, close to which the pipe A is inserted, and D is the movable uppermost board pressed upon by the 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 eight. 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 Ib. 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 (he 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.
Biowng Engines.—Where larger quantities of air at higher pressures than con 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" or "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 utilised, so that when it is moving io either direction suction will be taking place on one side and delivery on the other. All processes in connexion with which
blowing engines are used require the air to be nbove the pressure of the outer atmosphere. This means that the di&chargc valve* 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 tu the discharge chamber.
The power used lo 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 lo 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. TTic engines are generally buik 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 cost 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 ihc steam piston rod, so that as the steam piston comes up the air piston goes down and r;Vc versa. At the steam end of the beam a third connecting rod works the crank of a flywheel shaft.
About the end of the iath century an important development took place which consisted in using the waste gas from M. • furnaces lo form with air nn explosive mixture, and emplnying this mixture to drive the piston of the actuating cylinder in precisely the sjmc manner as the explosive mixture of coal gas and aif is used in a gas engine. Since the majority of Mowing engines are used for providing the air required in iron bhst furnaces, considerable saving should be effected in this way, because the gas which escapes from the lop of the furnace b 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
FlG. 3.—Section of Cylinder of Early Blowing Engine (1851).
internal view of one of the blowing cylinders ol the engine erected at the Dowlais Ironworks as far back as i&5t. M*ny of the details arc now obsolete, but the general scheme Is the same as in all blowing engines. Here A is the air cylinder; in t his » & piston whose rod is marked R; this piston b usually made air-tight by some form of packing fitted into the groove which runs round its edge. In this particular case the cylinder ii plactd vertically and its piston nxj is actuated from ihe end of a reeling beam. The ton and bottom ends arc dosed by coven and in i !u -. are a number of openings controlled by valves opening inwards 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 v at the top, and the air in the space A below the piston, drawn in during the previous up-slroke, is being expelled through the valve d 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-siroke 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.—Verticil Section of Ljckcnby Bloving Engines (1871). delivery of the air. The sir is therefore led from O into a large itorage 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 -., ivc to compensate for the irregularities, and • nearly uniform stream of air will flow from it. The valves ii1-' 'I 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 J 2 ft., giving a discharge of 44,000 cub. It. of air per minute, al a pressure of 4} Ib to the square inch,
A (a Mr design of blowing engine, built in 1871 for the Lockenby Iron-works, Middlesbrough, is shown in section in fig. 4, and h'of a type- which is still the most common, especially in the north of England. Here A, the high-pressure steam, cylinder,
and C, the low-pressure one, are placed in tandem with the air cylinders B, B, whose pistons they actuate. In these blowing cylinders the inlet valves in the bottom arc 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 arc 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. '1 lie 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 13,072 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 loth 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 arc each M in. in diameter, and the high and low pressure cylinders of the compound steam engine arc 30 in. and 64 in. respectively, while the common stroke of all four is 60 in. The pressure of the air delivered varies from 4} to 10 Ib 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 Brosof Sheffield for the North-Eastcm Steel Company at Aliddlesbrough (see Engineering^ January 6, 1005) the same arrangement was adopted as in that just described. The two air cylinders are each 90 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 Ib 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 seat ings 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 tban 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, Weslgarth & Co. of Middlesbrough about 1905. The gas cylinder is not shown. It will be seen that the an- cylinder il horizontal, and it is arranged
Co.'s Blowing Engine.
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 piiton at A air is being discharged, and follows the course indicated by the arrows, so as first to past into the annular chamber which forms a continuation of the