out through the exit-pipe by a weight or spring.

Piston Blowers.- For blast furnaces and for Bessemer steel converters, blowing engines of large size are employed. In the former, the strength of the blast sometimes is as high as 10 pounds per square inch. For the Bessemer converter, where a much greater pressure is required, it occasionally reaches 30 pounds per square inch. A blowing engine consists of a steam cylinder, an air cylinder, and a large air chamber, to ensure a uniform blast. Sometimes the latter is dispensed with, and large main pipes used instead. The blowing cylinder is of cast iron, with an airtight piston, which, as it ascends and descends with the motion of the engine, alternately inhales and expels the air at each end. To effect this, a series of valves are provided and these are arranged as follows: Inlet valves are placed on the top of the cylinder, and also on three sides of the box, but on the fourth side there are two outlet valves. These valves consist of numerous openings, against which leather flaps lie when they are shut. Valves of a similar nature are placed at the bottom of the cylinder. When the piston descends, it would create a vacuum in the upper portion of the cylinder, provided there were no openings in it; but the external air pressing on the inlet valves, opens them, and fills the space above the piston; at the same time, the outlet valves, which only open outward, are tightly closed by the air pressing inward from the pipe. Again, when the piston ascends, it compresses the air above it, and exactly reverses the action of the valves; that is to say, it shuts the inlet valves, opens the outlet valves, and allows the compressed air to pass along the outlet pipe, which is made of large size, so as to offer as little resistance as possible to the passage of the air. The valves at the bottom of the cylinder work exactly in the same way, the inlet valves opening when the piston ascends, and shutting when it descends, thus compelling the inhaled air to pass into the pipe, by the lower outlet valves. The air is conducted by the pipe into a receiver of large capacity, which serves to equalize the blast before it passes to the tuyeres. A blast engine at Shelton Ironworks, in England, with a blowing cylinder 8 feet 4 inches in diameter, a 9-foot stroke, 186 horse-power, and making 32 single strokes of the piston per minute, inhales 15,700 cubic feet of atmospheric air per minute; but this is compressed by the blowing cylinder to a pressure of 3 pounds per square inch above the atmosphere, which reduces the volume supplied by the cylinder to 13,083 cubic feet. Its volume, however, is largely increased again, when raised to the hot-blast temperature, before entering the furnace.

Jet Blowers. In the Catalan forges of Spain, the south of France, and some parts of the United States, there is a very ingenious water blowing-machine in use called a trompe; but it can only be advantageously employed where a fall of a few yards of water is available. A cistern to act as a reservoir for the water; pipes (generally two in number), through which it descends; and a wind-chest to allow the air and water to separate, constitute the essential parts of the apparatus. It is put in operation by lifting the wedge with a lever; this allows the water to rush down the pipe, and, in doing so, draws in air through sloping holes, called

aspirators, at the throat of the pipe. A continuous current of water and air is thus supplied to the wind-chest, which is provided with an opening for the escape of the water, while the air passes out in a regular stream by the nozzle-pipe. The height from which the water falls determines the tension of the blast; but the height seldom exceeds 27 feet, which gives a pressure of from 12 to 2 pounds to the square inch. The separation of the air from the water is greatly promoted by the current impinging on the platform.

Fans.-The fan is another machine for producing blasts of air. It is employed for such purposes as the melting of pig iron in foundries and for forge fires. It is also used as an exhaust to withdraw foul air from mines, public buildings, and ships. For mines it is occasionally of a very large size. The winnowing of corn is another application of it. The common blast fan is like a wheel with the arms tipped with vanes or blades, instead of being joined by a rim, and it is placed usually in an eccentric position, inside a chest, with central openings on each side for the admission of air. It is generally driven by steam power, and as it revolves, air is sucked in at the centre, drawn toward the tips, and impelled forward through the exit-pipe. Blast fans seldom exceed 3 feet in diameter. The number of revolutions made. per minute ranges from 700 to 1,800; but the pressure of the fan blast does not usually go beyond 6 ounces per square inch for ordinary foundry cupolas. Schiele's fan has numerous curved blades and is nearly noiseless. It does not require much power to drive it, and has been very much used. Lloyd's fan has also curved blades, but they are fewer in number than in Schiele's.

Positive Blowers.- These are machines introduced in comparatively recent years. They act by regular displacement of the air at each revolution, since their pistons or drums closely fit their cases. In this respect they differ from fans, because, although there were no outlet for the blast, a fan could be kept revolving, but in such a case a pressure blower would stop. The rotary blower of Roots, of Connersville, Ind., is one of the best known, and is now very largely used in producing blasts in metallurgical operations, as well as for other purposes, in the United States and Europe. Its most improved form consists of a pair of horizontal shafts traversing a case of the form of two semi-cylinders, separated by a rectangle equal in depth to the diameter of the semi-cylinders, and in width to the distance between the centres of the shafts. These shafts carry a pair of solid arms or pistons, the relative positions of which are maintained by external gearing at both ends provided with safety coverings. Each has a section somewhat resembling the figure "8", the action of which, as they revolve, takes the air in by an aperture at the bottom of the machine, and expels it with considerable pressure, if required, at the top. It gives a much greater pressure of blast than is attainable by the fan. Another machine of this kind, designed by J. G. Baker, of Philade!phia, is employed for the same purposes as Root's. It has a central drum with two vanes fairly fitting the two ends and the bored semicylindrical top of the case. Two lower drums, crescent-shaped in section, work by external gears at double the velocity of the central

drum, the vanes of which move successively through the opening in each of the lower drums. The latter turn so as alternately to form abutments to prevent escape of air from either the entrance or delivery side. These rotary blowers produce blasts from a few ounces up to 3 pounds per square inch.

Blowitz, Henri Georges Stéphane Adolphe Opper de, on-re zhôrzḥ stā-fän ad-ôlf op-per de blō-vitz, French journalist: b. Pilsen, Austria, 28 Sept. 1832; d. Paris, 18 Jan. 1903. He settled in France; was successively appointed professor of German in the Lycée of Tours and at Limoges, Poitiers, and Marseilles; was naturalized a French citizen in 1870; and became the Paris correspondent of the London Times in 1871. Laurence Oliphant was then the correspondent at Paris, and de Blowitz became his assistant. During the war of 1870-1 Mr. Oliphant was excluded from Paris during the siege by the Germans, but de Blowitz, by means of carrier pigeons, balloons, and numerous ingenious devices, kept his chief outside the city walls in formed as to what was going on within the beleaguered city. He was noted for his success in obtaining secret and important information long before it was ready for official promulgation; and for his personal interviews with Thiers, Bismarck, Comte de Chambord, Alfonso XII., Gambetta, the Comte de Paris, the Sultan of Turkey, Marquis Tseng, the King of Rumania, Leo XIII., Jules Ferry, Duclerc, Prince Lobanoff and many other eminent men of the time in Europe. Many of his disclosures in his ietters to the Times, such as the text of the Treaty of Berlin, which he forwarded before it had been signed, created much excitement throughout Europe. He contributed more than 4,000 columns to the Times; was made an officer of the Legion of Honor, an officer of the Institute of France, and doctor of philosophy. He published Feuilles Volantes' (1858); L' Allemagne et la Provence (1869); Le Mariage Royal d'Espagne) (1878); Une Course à Constantinople (1884). He retired from his position as Times correspondent only three weeks prior to his death.

Blowpipe, an instrument by means of which the flame of a candle, a gas-jet, etc., is made to produce an intense heat, being then employed for a variety of useful purposes. Its most usual form is described in the article on blowpipe analysis (q.v.). It is employed by jewelers and goldsmiths in the work of soldering, and by other workers on small metallic objects; by the glassblower in making thermometers, barometers, and other glass instruments; by the enameler; and indeed wherever it is required to subject a small body to a strong heat. It has undergone a variety of improvements in the hands of the chemist, to whose researches it has proved an excellent auxiliary. Wollaston's portable blowpipe is formed of three pieces fitted into one another when in use, but which may be taken down and made to slide within each other. Most laboratory blowpipes have a hollow bulb or enlarged part at or near the end, the object of which is to condense the vapor of the breath, which often proves injurious in the common form of the instrument. To prevent corrosion from the action of the moisture, the bulb is made either of silver or sheet-tin, and it is capable of being opened in order that

it may be more easily cleaned. A little practice is necessary to enable the operator to keep up a constant blast for any length of time, the current of air being propelled through the pipe by the muscular exertion of the cheeks, while respiration is carried on through the nose. But when the process has to be long continued, the the form commonly used by glassblowers. The current of air is supplied by bellows. This is gas blowpipe, commonly called the oxyhydrogen blowpipe, is a very important and intensely powerful variety, whose structure is due to Mr. Newman of London. Sir Humphry Davy suggested the employment of other gases instead of common air, and Dr. Clarke of Cambridge adopted the suggestion. Dr. Clarke found that a mixture of two volumes of hydrogen and one of oxygen produced the greatest effect. These gases are contained in a bladder attached to the end of a pipe which leads into a vertical cylinder, in which is fitted a piston, working through a collar at the top. By the action of this piston the gas from the bladder is compressed into a copper chamber, and thence issues to the flame through an ordinary blowpipe nozzle. To guard against explosions, the gases are kept in separate holders, and by means of a special kind of burner are prevented from mixing until they other species of blowpipe, and many uses to are just going to be burned. There are various which they may be applied. For information on the subject see Plattner, On the Blowpipe' to whom the present form of the instrument is

due.

Blow'pipe Analysis, a branch of chemical analysis in which the composition of the substance under examination is inferred from its behavior when subjected to certain flame tests. The blowpipe itself commonly consists of a tapering brass tube about eight inches long, provided with a bell-shaped mouthpiece at one end, and at the other with a nozzle that is turned at right angles to the general length of the instrument. The nozzle should be tipped with platinum, and provided with a very minute perforation through which the operator blows a tiny blast of air that drives the flame of his lamp against the object to be analyzed. The flame used in blowpipe work should not be round and colorless, like those of spirit lamps and Bunsen burners, but should be flat and luminous, containing plenty of free, incandescent carbon. A large candle-flame serves very well, although it is not flat. Usually a gas-flame is employed, in connection with a burner formed by flattening a piece of brass tubing, and then cutting it off at the top, at an angle. When the blowpipe is in service its tip is introduced into the flame of the lamp, which the air-blast deflects laterally in the form of a long, almost non-luminous cone, which consists of two visibly different portions. The inner part is somewhat brighter, and is richer in unoxidized gases. The outer layer, being more plentifully supplied with oxygen, consists almost entirely of completely oxidized gases. The outer portion of the blowpipe flame is called the "oxidizing flame," since this part, when directed against the specimen under examination, heats it while it is in contact with the air, and causes it to oxidize, if it is capable of doing so at the temperature that is attainable by the blowpipe. The inner portion of the flame is called the "reducing flame,"

from the fact that when the specimen is exposed to this part, it is heated, not in contact with the air, but while surrounded with an atmosphere of partially unoxidized hydrocarbon gases. Under these circumstances many metallic oxides give up their oxygen to the hot hydrocarbon gases in which they are bathed, and are themselves reduced to the metallic form. If a flame still richer in free carbon and unconsumed hydrocarbons is desired, the tip of the blowpipe is held just outside of the lamp-flame, and a jet of flame with a luminous tip containing particles of solid carbon can easily be thrown down upon the specimen.

In blowpipe analysis there is no recognized "scheme" to be followed out. The method is oftenest used for the determination of minerals, and in such cases the analyst usually has some sort of idea, in advance, of the elements that may possibly be present. The substance to be examined is usually first pulverized, and a portion of it heated in a tube that is open only at the upper end. If it carbonizes, it contains organic matter of some kind, and the odor that is produced is often a good indication as to whether the organic matter is of an animal or vegetable nature. If the substance, when heated in the closed tubes, gives off water which condenses in the upper part of the tube, the moisture so condensed should be tested with litmus paper. If it is neutral, the substance is a hydrated compound, or a hydroxide. An acid reaction indicates acid salts, and an alkaline one may usually be taken to indicate the presence of compounds of ammonia. If the substance melts but does not change its color, it is an alkaline or a hydrated salt. If it melts and turns yellow, remaining yellow even after cooling, it contains oxide of bismuth; while if it melts to a yellow color, but turns red upon cooling, it contains oxide of lead. If it does not melt, but changes color, the indications are as follows: Yellow, both hot and cold, indicates stannic oxide; if yellow while hot, but white when cold, zinc oxide; if black while hot, and reddish-brown when cold, ferric oxide; if black while hot, but bright red when cold, mercuric oxide. If gas is evolved, its nature should be determined. Oxygen may be detected by the kindling of a glowing splinter of wood inserted into the tube; carbon dioxide by its extinguishing such a spark promptly; carbon monoxide by the gas burning with a bluish flame when ignited at the mouth of the tube; sulphur dioxide, ammonia and cyanogen, by the odor. Oxygen indicates chlorates, peroxides, etc.; carbon dioxide indicates carbonates or oxalates; carbon monoxide indicates oxalates or formates; sulphur dioxide indicates certain sulphites or sulphates; cyanogen indicates cyanides; and ammonia indicates some compound of that substance. If the gas is reddish-brown in color, bromides, nitrates, or nitrites, are probably present; if it is violet, an iodide is indicated. A sublimate may also be deposited upon the tube. If the sublimate is black, or nearly so, selenium or mercuric sulphide are indicated; if yellow, sulphur or a sulphide; if white, a salt of ammonia or mercury, a volatile organic acid, or an oxide of antimony or arsenic. Gray metallic globules indicate mercury, and a metallic mirror may represent either antimony or arsenic.

When the substance is heated in an inclined tube, open at both ends, similar indications are

to be observed; modified somewhat, however, by the fact that oxygen can now pass up through the tube and come in contact with the specimen under examination. Thus sulphides are commonly oxidized in the open tube, arsenic will sublime as the trioxide and not as the metal, and selenium gives a sublimate that may be gray or red, and also a strong odor of horseradish.

The color that the specimen communicates to the non-luminous part of the flame is likewise of great service in determinations by the blowpipe. A piece of platinum wire, bent at the end into a small loop, is dipped in hydrochloric acid and held in the flame, this process being repeated several times until the analyst is confident that the wire itself is free from any substance that can color the flame. The little loop at the end is then brought into contact with some of the finely pulverized specimen, and introduced into the flame again. Sodium gives a strong lasting yellow; calcium an orange red; lithium and strontium a crimson; potassium a lavender; barium an apple green; thallium, copper, and boracic acid a brighter green; lead and antimony a pale blue; selenium a deep blue. The yellow due to sodium is so powerful, even when that metal is present only in slight amounts, that the colors due to the other metals present are sometimes difficult to observe by the unaided eye. Hence colored glasses are often used, through which to take note of the flame color; the tint of the glass being selected so as to cut off the yellow light of the sodium, while allowing the particular color that is sought to pass through unobstructed. Cobalt blue glass, for example, is used in this way in testing, by flame coloration, for potassium.

When a sample of the specimen to be analyzed is heated upon charcoal, it is often possible to obtain some of the elements that are present, in the form of a metallic bead, by the reduction of their oxides or of the other compounds in which they were originally contained. Lead, tin, and silver give beads that are white and malleable; copper gives a malleable red bead; antimony and bismuth give brittle beads; and iron, cobalt, and nickel may often be obtained in the form of gray, magnetic powders.

While the substance is being heated upon charcoal, an incrustation commonly forms on the charcoal, from the character of which useful inferences can be drawn. Thus antimony gives a white incrustation; bismuth, an incrustation that is deep yellow when hot and lighter yellow when cold; lead, one that is light yellow when hot and deep yellow when cold, and is surrounded by a white border; arsenic gives a white incrustation that is very volatile; and with zinc the color is yellow when hot and white when cold.

Many metallic oxides are soluble in melted borax, and valuable color indications are obtained by heating small quantities of the substance in little beads of melted borax, that are held in the flame upon tiny loops of platinum wire. The phenomena that are observed in this way are quite complicated, however, and for an account of them the manuals on blowpipe analysis should be consulted. See Cornwall,

Manual of Blowpipe Analysis'; Moses and Parsons, 'Elements of Mineralogy, Crystallography, and Blowpipe Analysis'; Dana, 'Minerals and How to Study Them.'

diers, who loved him as a father. His addresses and proclamations are distinguished for their brevity, precision, and simplicity. Consult 'Blücher's Life,' by Varnhagen von Ense (Berlin 1827); and Scherr's Blücher's Life and Times (Leipsic 1862).

Blue, Victor, American naval officer: b. North Carolina, 6 Dec. 1865. He graduated at the naval academy June 1887, and serving through the grades of ensign and junior lieutenant, was promoted lieutenant 3 March 1899. At the outbreak of the war with Spain he was ordered to the gunboat Suwanee, and while on duty off the Cuban coast captured two Spanish patrol sloops having on board a heliographic signal outfit. On II June 1898 he landed at Aserraderos, passed through the Spanish lines, proceeded to the hills overlooking Santiago city and harbor, where he located the Spanish fleet commanded by Admiral Cervera. On 25 June he made a further reconnoissance and mapped the position of the Spanish ships. To accomplish these things he traveled a distance of nearly 140 miles, mostly through territory occupied by the intrenchments of the Spanish army. Admiral Sampson highly commended the manner in which these tasks had been performed and recommended that Lieut. Blue be advanced ten numbers as a promotion. He was placed in command of the captured gunboat Alvarado, and on 12 Aug. 1898 bombarded the fortifications of Manzanillo. Subsequently he served in China and the Philippines.

Blue, one of the seven primary colors. The blue pigments commonly employed by artists are few in number, including native and artificial ultramarine, cobalt, indigo, and Prussian blue. Genuine ultramarine, prepared from the mineral lapis lazuli, and ordinary cobalt blue, sold for artists' work, are permanent colors. They are used either alone, or mixed with other pigments, chiefly for skies and distances in landscape, and by themselves, or to make up grays and other mixed tints in figure painting; Owing to the exceptionally high price of real ultramarine, the artificial color, which is of doubtful permanency, is usually substituted for it. Prussian blue and indigo are highly useful colors, since it is only these that yield dark blues, and only from them, mixed with yellows or browns, that strong greens can be obtained. It is unfortunate accordingly that both are more or less fugitive. All the blues above named are used both in oil or water color painting, but indigo less than the others in oil, since it is most apt to fade in that medium.

A number of different names are used in commerce for what is essentially the same pigment, or for pigments closely resembling one another. The following statement gives some explanation of these: Cobalt blues are mixtures of cobalt with earthy or metallic bases, which have been subjected to the action of heat, and have received the following names: Cobalt blue, cerulean blue, royal blue, Ďumont's blue, Saxon blue, Thénard's blue, Leithner's blue, Hungary blue, Zaffre or enamel blue, Vienna blue, azure blue, and Paris blue. The last name is also applied to a Prussian blue, and azure is also given to a variety of ultramarine blue. Smalt is a powdered cobalt glass used in illumination and flower painting. Artificial ultramarine is also called French ultramarine, French blue, new

blue, and permanent blue. Coarse qualities of this color are largely used by house painters. Intense blue is a refined indigo. Prussian blue (sesqui-ferrocyanide of iron) is otherwise named Berlin blue, Paris blue, and ferrocyanide of iron. The name Paris blue is also given to a sian blue made lighter by the addition of an cobalt color. Antwerp blue is a variety of Prusaluminous base, and not so permanent. Blue ochre (hydrated phosphate of iron) is a subdued permanent blue, but not much employed. Blue verditer is a hydrated oxide of copper which changes and ultimately blackens by time. Blue was adopted as their distinctive color by It is used in distemper work and paper staining. the Scottish Covenanters in the 17th century and is the usual color of the uniforms of the soldiers of the United States army. A dark shade of this color is generally worn by the sailors of most countries, whence the term navy blue is derived.

Blue Beech. See HORNBEAM.

Blue Bird, or the North American thrush, is widely distributed throughout the United States, where it holds a similar place, in the hearts of the people, as the redbreast in England. In fact, locally, it is sometimes termed "blue-robin." It is a smaller bird than the rest of the thrushes. Its whole upper parts are sky blue, shot with purple, with its throat, neck, breast, and sides reddish chestnut, and part of its wings and its tail feathers black. The "soft and agreeable warble" of the bluebird is one of the first and most welcome sounds of bird-music, that we hear in the early spring. The male is remarkably attentive to his more pride in their five or six pale-blue eggs, laid protectively colored mate, and takes exuberent in holes in the trees of gardens, and often also in bird-boxes, and in the crevices in the walls of outbuildings. There are often two broods in a season. The bluebird fights hard to protect his small, neatly constructed nest from the housemake his life miserable by their intrusion on his sparrow, swallows, wrens, and other birds, which domestic privacy. Several other sorts of birds, of other countries, prevailingly blue in color, receive the name "bluebird," such as the "Oriental fairy-bluebirds" of the genus Irena, more particularly Irena puella, one of the East Indian bulbuls.

Blue Books, the official reports, papers, and documents printed for the British government to be laid before the Houses of Parliament. They are so called simply from being stitched up in blue paper wrappers, and include bills presented to, and acts passed by, the houses; reports and papers moved for by members or granted by government; reports of committees; statistics of trade, etc. The term is used also in a broad way as descriptive of special reports put forth by the government of any country or its various

executive departments. In the United States the published lists of government employees and the navy regulation manual are known as Blue Books and the foreign diplomatic correspondence is commonly issued in Red Books. French official reports, etc., are called Yellow Books; those of Italy are styled Green Books, and those of Spain Red Books.

Blue Boy, The, a celebrated picture by Gainsborough, dated 1679; its subject, a boy dressed in a blue satin 16th century costume.