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bers 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 con

densed 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 plati num wire. The arrange ment is represented in fig. G. It will be ob served that the pipe con veying 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.

FIG. 6. -Hot-Blast Blowpipe.

The power of the blowpipe flame may be greatly in creased by supplying oxygen in the place of atmospheric air ; and a still greater heat is obtained by the combina tion of pure oxygen and hydrogen. In the latter arrange ment, which constitutes the oxyhydrogen blowpipe, it is important that the oxygen and hydrogen be kept in sepa rate 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 rn.it dem Luthrohre, 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 Loth- rohrbuch, translated by Professor II. B. Blanford, and a Manual of Determinative Mineralogy, ivith 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, Gerhard 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 after wards entered into the service of Prussia, in which he became distinguished by his activity; but conceiving him self neglected be the great Frederick, he became a farmer in Silesia, and by his enterprise and perseverance in fifteen years he acquired an honourable independence. On the accession of Frederick-William II. lie was recalled to mili tary 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 Liibcck, 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 Konigsberg, 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, chic-fly 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 interven tion of the other allied commanders, he was disposed to make a severe retaliation for the calamities that Prussia hud 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 defeated in the severe battle of Ligny on 1 Gtli of June ; yet, with his characteristic spirit and energy, Bliicher 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 Blucher 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 Blucher remained for several months; but the health of the aged commander having declined, he retired to his Silesian residence at Kirblowitz, where he died on the 12th September 1819, aged seventy-seven. The life of Bliicher has been written by Varnhagen von Ense (1827), Rauschnick (1836), Bieske (1862), and Scherr (1862).

BLUMENBACH, Johann Friedrich, a distinguished

physiologist, was born at Gotha on the llth of May 1752. He studied medicine at Jena, aud afterwards at Got- tingen, where he took the degree of doctor in 1775. His thesis on that occasion De Generis Humani Varietate Nativa, published in quarto, was the germ of those cranio- logical researches to which so many of his subsequent inquiries were directed ; and such was the opinion enter tained of his acquirements, that he was appointed an adjunct or extraordinary professor of medicine in the following year, and ordinary professor in 1778; soon after which period he began to enrich the pages of the Medicin- ischc JJibllot/tek, of which he was editor from 1780 to 1794, with various contributions on medicine, phj-siology, and anatomy. In physiology he was of the school of Haller, and was in the habit of illustrating his theory by a careful comparison of the animal functions of man with these of the lower animals. His reputation was much extended by