tube, the hold being steadied by resting the elbow on the table. The mode of blowing is peculiar, and requires some practice; an uninterrupted blast is kept up by the muscular action of the cheeks, while the ordinary respiration goes on through the nostrils.

If the flame of a candle or lamp be closely examined, it will be seen to consist of four parts-(a) a deep blue ring at the base, (b) a dark cone in the centre, (c) a luminous portion round this, and (d) an exterior pale blue envelope. The blue ring is formed chiefly by combustion of carbonic oxide. In the central cone the combustible vapors from the wick, though heated, are not burned, atmospheric oxygen not reaching it. In the luminous portion the supply of oxygen is not sufficient for complete combustion; the hydrogen takes up all or most of it, and carbon is precipitated in solid particles and ignited. In the exterior envelope, lastly, the temperature is highest, and combustion most complete, sufficient oxygen being supplied to convert the carbon and hydrogen into water and carbonic acid.

In blowpipe work only two of these four parts are made use of, viz., the pale envelope, for oxidation, and the luminous portion, for reduction. To obtain a good oxidizing flame, the blowpipe is held with its nozzle inserted in the edge of the flame close over the level of the wick, and blown into gently and evenly. A conical jet is thus produced, consisting of an inner cone, with an outer one commencing near its apex:-the former, corresponding to (a) in the free flame, blue and well defined; the latter, corresponding to (d), pale blue and vague. The heat is greatest just beyond the point of the inner cone, combustion being there most complete. Oxidation is better effected (if a very high temperature be not required) the farther the substance is from the apex of the inner cone, so far as the heat proves sufficient, for the air has thus freer access.

To obtain a good reducing flame (in which the combustible matter, very hot, but not yet burned, is disposed to take oxygen from any compound containing it), the nozzle, with smaller orifice, should just touch the flame at a point higher above the wick, and a somewhat weaker current of air should be blown. The flame then appears as a long, narrow, luminous cone,-the end being enveloped by a dimly visible portion of flame corresponding to that which surrounds the free flame, while there is also a dark nucleus about the wick. The substance to be reduced is brought into the luminous portion, where the reducing power is strongest.

The flame of an oil-lamp is the best for blowpipe operations where gas is wanting; candle flame may be used when great heat is not required. The blowpipe lamp of Berzelius, supplied with colza oil, is probably the most suitable. The wick, when in use, should be carefully trimmed and clean, so as to avoid a smoking flame. The general introduction of gas has quite driven out the use of oil-lamps for blowpipe purposes in laboratories.

Various materials are used as supports for substances in the blowpipe flame; the principal are charcoal, platinum, and glass. Charcoal is valuable for its infusibility and low conductivity for heat (allowing substances to be strongly heated upon it), and for its powerful reducing agency by the production of carbonic oxide when ignited; so that it is chiefly employed in trying the fusibility of minerals, and in reduction. The best kind of charcoal is that of close-grained pine or alder; it is cut in short prisms, having a flat smooth surface at right angles to the rings of growth. In this a shallow hole is made with a knife or borer, for receiving the substance to be held in the flame. Platinum is employed in oxidizing processes, and in fusion of substances with fluxes with a view to try their solubility in them, and note the phenomena of the bead; also in observing the coloring effect of substances on the blowpipe flame (which effect is apt to be somewhat masked by charcoal). Most commonly it is used in the form of wire, with a small bend or loop at the end. In flux experiments this loop is dipped when ignited in the powdered flux (e.g., borax), then held in a lamp flame till the powder is fused; and the process is repeated, if necessary, till the loop is quite filled with a bead of the flux; to this is now added a little of the substance to be examined. Platinum is also used in the form of foil and of spoons, and for the points of forceps. Metals and easily reducible oxides, sulphides, or chlorides should not be treated upon platinum, as these substances may combine with and

damage it. Tubes of hard German glass, 5 to 6 inches long, about 4th inch diameter, and open at both ends, are useful in the examination of substances containing sulphur, selenium, arsenic, antimony, and tellurium; these, when heated with access of air, evolve characteristic fumes. They are put in the tube near one end (which is held slightly depressed), and subjected to the blowpipe flame. The sublimates often condense on the cooler parts of the tube. Small tubes, closed at one end, are used, where it is required to detect the presence of water, mercury, or other bodies which are volatilized by heat without access of air. The most important fluxes used in blowpipe analysis are carbonate of sodium, borax, and microcosmic salt. The first (which must be anhydrous and quite free from sulphates) serves chiefly in reducing metallic oxides and sulphides on charcoal, decomposing silicates, determining the presence of sulphur, and discriminating between lime and other earthy bases in minerals. Pure borax, or acid borate of sodium deprived of its water of crystallization by heating, is used for the purpose of dissolving up metallic oxides, when in a state of fusion at a red heat, such fused masses usually having characteristic colors when cold. In some cases the color and transparency change on cooling. Microcosmic salts, or ammonio-phosphate of sodium, is used on platinum wire in the same way as borax;1 on heating, water and ammonia are given off. The following are some other reagents for certain cases-nitrate of potash, bisulphate of potash, nitrate of cobalt, silica, fluoride of calcium, oxide or oxalate of nickel, protoxide of copper, tinfoil, fine silver, dry chloride of silver, bone ash, and litmus and Brazil-wood paper.

It may be useful here to pass briefly under review a few of the effects obtained in qualitative examinations with the blowpipe. Beginning with the closed tube, organic substances may be revealed by the empyreumatic odor given off, and by charring. Mercury condenses on the tube in minute globules. Selenium gives a reddish-brown, tellurium a grey, arsenic a black sublimate. Oxygen is sometimes given off, and will inflame an incandescent splinter of wood when introduced; while ammonia may be detected by red litmus paper, as also the acid or alkaline reaction of any liquid product. In the open tube, sulphur and sulphides give off pungent-smelling sulphurous acid gas. Selenium gives a steel-grey deposit, and an odor resembling that of horse radish. Arsenic, antimony, tellurium, yield their respective acids, forming white sublimates. The deposit from arsenic is crystalline, that from the others amorphous. In examination on charcoal, it is useful, in practice, to commence with pure materials and familiarize one's self with their phenomena. Most of the metals fuse in the heat of the blowpipe flame; and in the outer flame they oxidize. The noble metals do not oxidize, but they fuse. The metals platinum, iridium, rhodium, and palladium do not fuse. The incrustations (when such occur) are in each case characteristic, both in aspect and in the effects they give before the blowpipe flame. Among the most common oxides capable of reduction on charcoal alone, in the inner flame, are those of zinc, silver, lead, copper, bismuth, and antimony. The principal minerals that cannot be so reduced are those containing alkalies and alkaline earths, and the oxides of iron, manganese, and chromium. Many substances give a characteristic color, when held by platinum forceps in the oxidizing flame. For example, arsenic, antimony, lead, color the flame blue; copper, baryta, zinc, green; lime, lithia, strontia, red; potash, violet. Heated with borax, some bodies give a clear bead, both while hot and cold, except when heated by the intermittent oxidizing flame, or the flame of reduction, when the bead becomes opalescent, opaque, or milky white. The alkaline earths, tantalic and titanic acids, yttria and zirconia are examples of this. The oxides of most of the heavy metals give colored glasses with borax, similar to those obtained by their use in glass or enamel painting. Thus oxide of cobalt gives a showy blue, and oxide of nickel a reddish-brownish color, both being very characteristic and delicate tests of the presence of these metals. Ferric oxide gives a feeble yellow color, which is darker while hot; but when the bead so colored is treated in the reducing flame the iron passes into the state of ferrous oxide, giving an intensely green or nearly black

The soldering lamp of tinners is an example of the æolipile, an instrument which deserves some notice here. The spirit lamp a (fig. 4) is inserted at the bottom of a sheet-iron cylinder MN, which is open on one side, as shown. The upper part of the cylinder supports a strong cup of M hammered metal, with an opening for spirits at the top (closed by a screw or cock), and a bent tube coming down from its upper part, through a slit in the cylinder to the back of the flame. The weak spirits which are put in the cup are caused to boil by the heat of the lamp, and the vapor, escaping through the bent tube, produces a jet of very hot flame.

(The cup is shown separately in fig. FIG. 4.-Soldering 5.) Similar advantage is gained by causing air to pass through a quan

Lamp.

N

tity of some soluble hydrocarbon before it goes to the nozzle of a blowpipe.

There are several forms of apparatus in which water pressure is utilized for supplying a steady blast to the blowpipe. One of these consists of a tin case, with an oblique partition reaching nearly to the bottom. The case is filled nearly three-fourths with water. Air is blown into the compartment which narrows upwards (and

with which the nozzle is connected FIG. 5.-Cup of fig. 4. above) by a pipe reaching nearly

to the bottom. This air rises through the water and accumulates above it, forcing the water up into the other compartment, which communicates freely with the outer air. The difference of water-level in the two chambers thus sustains a continuous blast through the nozzle. Blowpipes have also been made on the principle of the blowing-machine known as the trompe. Again, the blast is sometimes supplied from a chamber in which air is condensed by means of a syringe. The absorption of heat when an ordinary blast of cold air (with its large proportion of nitrogen) is sent into a flame is considerable; and this has suggested the employment of a hot blast for blowpipe work. Mr. T. Fletcher has constructed an apparatus on this principle, which yields a very intense flame, sufficient to fuse platinum wire. The arrangement is represented in fig. 6. It will be observed that

FIG. 6.-Hot-Blast Blowpipe. the pipe conveying the blast is coiled several times round the gas pipe (for ordinary coal-gas), and that both coil and core are heated by a row of burners placed below. The blast is furnished either with the mouth or with india-rubber bellows.

The power of the blowpipe fiame may be greatly increased by supplying oxygen in the place of atmospheric air, and a still greater heat is obtained by the combination of pure oxygen and hydrogen. In the latter arrangement, which constitutes the oxyhydrogen blowpipe, it is important that the oxygen and hydrogen be kept in separate reservoirs, and be only allowed to mix at the jet, otherwise explosion may occur through the flame running

back through the jet to the reservoir of mixed gases. There are various methods of effecting this, which we do not stop to describe. The blue flame produced gives the most intense heat that is obtainable by artificial means, except by the electric current. Thick platinum wires are melted before it like wax in a candle flame; and earths, such as lime, magnesia, or zirconia, are raised to intense incandescence. For the application of the oxyhydrogen blowpipe to the fusion of the more refractory metals, see PLATINUM.

The literature of the blowpipe is very extensive. The earlier notices of the subject will be found in Berzelius's original work, of which there are English translations by Children, published in 1822, and by J. D. Whitney (of a later edition), published in Boston in 1845. The most complete work, however, is Plattner's Probirkunst mit dem Löthrohre, of which there are several editions; the fourth or latest, published since the author's death, has been edited by his pupil and successor, Professor Richter of Freiberg. An English translation, by Professor H. B. Cornwall, has been published in New York. For the use of the blowpipe in determining minerals, the best works are Scheerer's Löthrohrbuch, translated by Professor H. B. Blanford, and a Manual of Determinative Mineralogy, with an Introduction to Blowpipe Analysis, by Professor G. J. Brush of Yale College. In addition to these works, notices, more or less extensive, will be found in most mineralogical handbooks and works on chemical analysis. (A. B. M.)

BLÜCHER, GEBHARD LEBERECHT VON, field-marshal of the Prussian armies, prince of Wahlstadt in Silesia, was born at Rostock in 1742. In his fourteenth year he entered into the service of Sweden; and in the war between that power and Prussia he was taken prisoner. He afterwards entered into the service of Prussia, in which he became distinguished by his activity; but conceiving himself neglected by the great Frederick, he became a farmer in Silesia, and by his enterprise and perseverance in fif teen years he acquired an honorable independence. On the accession of Frederick-William II. he was recalled to military service, and replaced as major in his old regiment, the Black Hussars, where he distinguished himself in six general actions against the French, rose to the rank of colonel and major-general in 1793-4, and gained a high reputation by his energy, promptitude, and foresight. He was in a subordinate command in the disastrous battle of Jena in 1802; but he made a masterly retreat with his column to Lübeck, and extorted the praises of his adversaries, who testified on his capitulation that it was caused by "want of provisions and ammunition." He was soon exchanged for General Victor, and was actively employed in Pomerania, at Berlin, and at Königsberg, until the conclusion of the war. When Prussia shook off the French yoke in 1813, he first obtained a separate command. At the head of 60,000 troops, chiefly composed of raw militia, he defeated four French marshals at Katsbach, and rapidly crossing the Elbe, materially contributed to the signal victory of Leipsic. In several severe actions he fought his way to Paris, which he entered on 31st March, 1814; and there, it has been stated, but for the intervention of the other allied commanders, he was disposed to make a severe retaliation for the calamities that Prussia had suffered from the armies of France. Blowing up the bridge of Jena across the Seine was said to be one of his contemplated acts. When war again broke out in 1815, the veteran was at the head of the Prussian armies in Belgium, and exhibited his wonted enterprise and activity. But partly owing to his own confidence and temerity, partly to the skilful strategy of his celebrated opponent, he was de feated in the severe battle of Ligny on 16th of June; yet, with his characteristic spirit and energy, Blücher rallied his defeated forces, and appeared on the field of Waterloo on the 18th, just as Wellington had repulsed the last attack of Napoleon on the British position. At that critical moment Blücher was seen emerging from the wood of Frichemont on the French right; and the simultaneous irresistible charge of the British forces converted the retreat of the French into a tumultuous flight. The allied commanders met on the Genappes road, near the farm called Maison du Roi, where the British forces were halted. The pursuit was continued through the night by sixteen fresh Prussian regiments with terrible carnage. The allies soon again entered Paris, where Blücher remained for several months; but the health of the aged commander having declined, he

the rutting season. At the same time, the canines of the upper jaw begin to develop outwards and upwards, and these take the place of the lower ones as offensive weapons. The wild boar is a native of the temperate regions of Europe and Asia, where it inhabits the deepest recesses of forests and marshy grounds. Vambery, in his recent journey through Central Asia, found them in enormous numbers in the extensive swamps of Turkestan. They appear to have been denizens of British forests at least till the reign of Henry II., after which they are not heard of till the time of Charles I., when an attempt to restock the New Forest with them failed. In the reign of William the Conqueror any one killing a wild boar was liable to have his eyes put out. After reaching maturity the boar becomes a solitary animal, unless during the breeding season, when it seeks the female, and at this time they engage in fierce contests with each other, although these, it is said, seldom lead to fatal results, as they contrive to receive the blows on their tusks, or on the specially tough skin which covers their shoulders. The Indian Wild Boar (Sus indicus) is undoubtedly polygamous, and there are several facts which point to a similar habit in the European boar. Both species are nocturnal, issuing from their coverts at twilight in quest of food. This is chiefly of a vegetable nature, consisting of roots which it ploughs up by means of its broad muscular snout and of grain; although they are also known to devour the smaller mammals, birds, and eggs. The female is ordinarily a timid creature, but shows great courage and fierceness in defence of its young. It associates with other females for mutual protection against wolves. The wild boar was for many centuries a favorite beast of chase with the nobility of Europe. It was hunted on foot with the spear,-its great strength, and its ferocity when at bay, rendering the sport alike exciting and dangerous. The gun has now superseded the spear in European boar-hunting, but owing to the comparative scarcity of the boars it is now little practised. In India, however, where these animals abound in the jungles, it is still a favorite sport, the boar being pursued on horseback and speared. The bristles of the Boar are much used in the manufacture of brushes.

BOAT-BUILDING. See SHIP-BUILDING. BOBRUISK, a town of Russia, in the government of Minsk, 110 miles S.E. of that city, in 53° 15′ N. lat. and 28° 52′ E. long., on the right bank of the Berezina, near the confluence of the Bobruiska, on the high road from Mogileff to Brest-Litovsk. Bobruisk was an unimportant place in 1508, when the Moscovite army, sent by the Emperor Basil against the Polish king Sigismund, advanced towards it. In the 17th century there existed a castle, which was burned down in 1649. When the Minsk government was incorporated with Russia, Bobruisk was a small borough; but in 1795 it was raised to the rank of chief town of a department in the Minsk government. In the beginning of the reign of Alexander I. there was erected at Bobruisk, by the advice of General Osterman, a fort, which obtained great importance in 1812, and was made equal to the best in Europe by the Emperor Paul I. The fort proper is built on a height exactly at the confluence of the Bobruiska with the Berezina, nearly a mile from the town. On the right bank of the former river is another small fort, called Fort Frederick William, well supported by a line of defences. In 1860 the population of Bobruisk was 23,761, of whom 11,394 were Jews. It has 2 Greek churches, 17 synagogues, a military hospital, and a departmental college. The only industrial establishments are two potteries. On the river near the town there is a harbor, by which grain and salt are imported from the southern governments.

BOCCACCIO, GIOVANNI. Comparatively little is known of Boccaccio's life, particularly of the earlier portion of it. He was born in 1313, as we know from a letter of Petrarch, in which that poet, who was born in 1304, calls himself the senior of his friend by nine years. The place of his birth is somewhat doubtful,-Florence, Paris, and Certaldo being all mentioned by various writers as his native city. Boccaccio undoubtedly calls himself a Florentine, but this may refer merely to the Florentine citizenship acquired by his grandfather. The claim of Paris has been supported by Baldelli and Tiraboschi, mainly on the ground that his mother was a lady of good family in that city, where she met Boccaccio's father. The balance of evidence is decidedly in favor of Certaldo, a small town or castle in the

valley of the Elsa, 20 miles from Florence, where the family had some property, and where the poet spent much of the latter part of his life. He always signed his name Boccaccio da Certaldo, and named that town as his birthplace in his own epitaph. Petrarch calls his friend Certaldese; and Filippo Villani, a contemporary, distinctly says that Boccaccio was born in Certaldo.

Boccaccio, an illegitimate son, as is put beyond dispute by the fact that a special license had to be obtained when he desired to become a priest, was brought up with tender care by his father, who seems to have been a merchant of respectable rank. His elementary education he received from Giovanni da Strada, an esteemed teacher of grammar in Florence. But at an early age he was apprenticed to an eminent merchant, with whom he remained for six years, a time entirely lost to him, if we may believe his own statement. For from his tenderest years his soul was attached to that "alma poesis," which, on his tombstone, he names as the task and study of his life. In one of his works he relates that, in his seventh year, before he had ever seen a book of poetry or learned the rules of metrical composition, he began to write verse in his childish fashion, and earned for himself amongst his friends the name of "the poet." It is uncertain where Boccaccio passed these six years of bondage; most likely he followed his master to various centres of commerce in Italy and France. We know at least that he was in Naples and Paris for some time, and the youthful impressions received in the latter city, as well as the knowledge of the French language acquired there, were of considerable influence on his later career. Yielding at last to his son's immutable aversion to commerce, the elder Boccaccio permitted him to adopt a course of study somewhat more congenial to the literary tastes of the young man. He was sent to a celebrated professor of canon law, at that time an important field of action both to the student and the practical jurist. According to some accounts-far from authentic, it is true-this professor was Cino da Pistoia, the friend of Dante, and himself a celebrated poet and scholar. But, whoever he may have been, Boccaccio's master was unable to inspire his pupil with scientific ardor. Again," Boccaccio says, "I lost nearly six years. And so nauseous was this study to my mind, that neither the teaching of my master, nor the authority and command of my father, nor yet the exertions and reproof of my friends, could make me take to it, for my love of poetry was invincible."

About 1333 Boccaccio settled for some years at Naples, apparently sent there by his father to resume his mercantile pursuits, the canon law being finally abandoned. The place, it must be confessed, was little adapted to lead to a practical view of life one in whose heart the love of poetry was firmly rooted. The court of King Robert of Anjou at Naples was frequented by many Italian and French men of letters, the great Petrarch amongst the number. At the latter's public examination in the noble science of poetry by the king, previous to his receiving the laurel crown at Rome, Boccaccio was present, without, however, making his personal acquaintance at this period. In the atmosphere of this gay court, enlivened and adorned by the wit of men and the beauty of women, Boccaccio lived for several years. We can imagine how the tedious duties of the market and the counting-house became more and more distasteful to his aspiring nature. We are told that finding himself by chance on the supposed grave of Virgil, near Naples, Boccaccio on that sacred spot took the firm resolution of devoting himself for ever to poetry. But perhaps another event, which happened some time after, led quite as much as the first mentioned occurrence to this decisive turning point in his life. On Easter-eve, 1341, in the church of San Lorenzo, Boccaccio saw for the first time the natural daughter of King Robert, Maria, whom he immortalized as Fiammetta in the noblest creations of his muse. Boccaccio's passion on seeing her was instantaneous, and (if we may accept as genuine the confessions contained in one of her lover's works) was returned with equal ardor on the part of the lady. But not till after much delay did she yield to the amorous demands of the poet, in spite of her honor and her duty as the wife of another. All the information we have with regard to Maria or Fiammetta is derived from the works of Boccaccio himself, and owing to several apparently contradictory statements occurring in these works, the very existence of the lady has been doubted by commentators, who seem