Worsted yarn spun on the English system, as well as woollen yarn and fabrics made from them, contain oil which has been incorporated with the wool to facilitate the spinning. This oil must be got rid of previous to bleaching, and this is effected by scouring in warm soap with or without the a.s.sistance of alkalis.

The actual bleaching of wool may be effected in two ways, viz. by treating the material either with sulphurous acid or with hydrogen peroxide. Sulphurous acid may either be applied in the gaseous form or in solution as bisulphite of soda. In working by the first method, which is technically known as "stoving," the scoured yarn is wetted in very weak soap containing a small amount of blue colouring matter, wrung or hydro-extracted and then suspended in a chamber or stove.

Sulphur contained in a vessel on the floor of the chamber is now lighted, and the door having been closed, is allowed to burn itself out. The goods are left thus exposed to the sulphur dioxide overnight, when they are taken out and washed in water. For piece goods a somewhat different arrangement is employed, the pieces pa.s.sing through a slit into a chamber supplied with sulphur dioxide, then slowly up and down over a large number of rollers and ultimately emerging again at the same slit. Wool may also be bleached by steeping in a fairly strong solution of bisulphite of soda and then washing well in water.

Wool bleached with sulphurous acid or bisulphite is readily affected by alkalis, the natural yellow colour returning on washing with soap or soda. A more permanent bleach is obtained by steeping the wool in hydrogen peroxide (of 12 volumes strength), let down with about three times its bulk of water and rendered slightly alkaline with ammonia or silicate of soda. Black or brown wools cannot be bleached white, but when treated with peroxide they a.s.sume a golden colour, a change which is frequently desired in human hair.

_Bleaching of Silk._

In raw silk, the fibre proper is uniformly coated with a proteid substance known as _silk-gum, silk-glue_ or _sericine_ which amounts to 19-25% of the weight of the material, and it is only after the removal of this coating that the characteristic properties of the fibre become apparent. This is effected by the process of "discharging" or "boiling-off," which consists in suspending the hanks of raw silk over poles or sticks in a vat containing a strong hot soap solution (30% of soap on the weight of the silk). The liquor is kept just below boiling point for two or three hours, the hanks being turned from time to time.

During the process, the sericine at first swells up considerably, the fibres becoming slippery, but as the operation proceeds it pa.s.ses into solution. It is important that only soft water should be used for boiling-off since calcareous impurities are liable to mar the l.u.s.tre of the silk.

The silk is now rinsed in weak soda solution and wrung. In this condition it is suitable for being dyed, but if it is to be bleached, the hanks are tied up loosely with smooth tape, put into coa.r.s.e linen bags to prevent the silk becoming entangled, and boiled again in soap solution which is half as strong as that used in the first operation.

The hanks are now taken out, rinsed in a weak soda solution, washed in water and wrung.

The actual bleaching of silk is usually effected by stoving as in the case of wool, with this difference, that the operation is repeated several times and blueing or tinting with other colours is effected after bleaching. Silk may also be bleached with peroxide of hydrogen, but this method is only used for certain qualities of spun silk and for tussore.

_Ornamental feathers_ are best bleached by steeping in peroxide of hydrogen, rendered slightly alkaline by the addition of ammonia. The same treatment is applied to the bleaching of _ivory_. If peroxide of hydrogen could be prepared at a moderate cost, it would doubtless find a much more extensive application in bleaching, since it combines efficiency with safety, and gives good results with both vegetable and animal substances. (E. K.)

FOOTNOTES:

[1] Besides being used for cotton goods, plate singeing is also employed for certain cla.s.ses of worsted goods (alpacas, bunting, &c.), and for most union goods (cotton warp and worsted weft).

[2] A machine working on this principle has been constructed by F.

Binder, and the makers of the machine (Messrs Mather & Platt, Ltd.) claim that it does better service than the machines constructed on the older principle.

BLEAK, or BLICK (_Alburnus lucidus_), a small fish of the Cyprinid family, allied to the bream and the minnow, but with a more elongate body, resembling a sardine. It is found in European streams, and is caught by anglers, being also a favourite in aquariums. The well-known and important industry of "Essence Orientale" and artificial pearls, carried on in France and Germany with the crystalline silvery colouring matter of the bleak, was introduced from China about the middle of the 17th century.

BLEEK, FRIEDRICH (1793-1859), German Biblical scholar, was born on the 4th of July 1793, at Ahrensbok, in Holstein, a village near Lubeck. His father sent him in his sixteenth year to the gymnasium at Lubeck, where he became so much interested in ancient languages that he abandoned his idea of a legal career and resolved to devote himself to the study of theology. After spending some time at the university of Kiel, he went to Berlin, where, from 1814 to 1817, he studied under De Wette, Neander and Schleiermacher. So highly were his merits appreciated by his professors--Schleiermacher was accustomed to say that he possessed a special _charisma_ for the science of "Introduction"--that in 1818 after he had pa.s.sed the examinations for entering the ministry he was recalled to Berlin as _Repetent_ or tutorial fellow in theology, a temporary post which the theological faculty had obtained for him. Besides discharging his duties in the theological seminary, he published two dissertations in Schleiermacher's and G.C.F. Lucke's _Journal_(1819-1820,1822), one on the origin and composition of the Sibylline Oracles "uber die Entstehung und Zusammensetzung der Sibyllinischen Orakel," and another on the authorship and design of the Book of Daniel, "uber Verfa.s.ser und Zweck des Buches Daniel." These articles attracted much attention, and were distinguished by those qualities of solid learning, thorough investigation and candour of judgment which characterized all his writings. Bleek's merits as a rising scholar were recognized by the minister of public instruction, who continued his stipend as _Repetent_ for a third year, and promised further advancement in due time. But the att.i.tude of the political authority underwent a change. De Wette was dismissed from his professorship in 1819, and Bleek, a favourite pupil, incurred the suspicion of the government as an extreme democrat. Not only was his stipend as _Repetent_ discontinued, but his nomination to the office of professor extraordinarius, which had already been signed by the minister Karl Altenstein, was withheld. At length it was found that Bleek had been confounded with a certain Baueleven Blech, and in 1823 he received the appointment.

During the six years that Bleek remained at Berlin, he twice declined a call to the office of professor ordinarius of theology, once to Greifswald and once to Konigsberg. In 1829, however, he was induced to accept Lucke's chair in the recently-founded university of Bonn, and entered upon his duties there in the summer of the same year. For thirty years he laboured with ever-increasing success, due not to any attractions of manner or to the enunciation of novel or bizarre opinions, but to the soundness of his investigations, the impartiality of his judgments, and the clearness of his method. In 1843 he was raised to the office of consistorial councillor, and was selected by the university to hold the office of rector, a distinction which has not since been conferred upon any theologian of the Reformed Church. He died suddenly of apoplexy on the 27th of February 1859.

Bleek's works belong entirely to the departments of Biblical criticism and exegesis. His views on questions of Old Testament criticism were "advanced" in his own day; for on all the disputed points concerning the unity and authorship of the books of the Old Covenant he was opposed to received opinion. But with respect to the New Testament his position was conservative. An opponent of the Tubingen school, his defence of the genuineness and authenticity of the gospel of St. John is among the ablest that have been written; and although on some minor points his views did not altogether coincide with those of the traditional school, his critical labours on the New Testament must nevertheless be regarded as among the most important contributions to the maintenance of orthodox opinions. His greatest work, his commentary on the epistle to the Hebrews (_Brief an die Hebraer erlautert durch Einleitung, ubersetzung, und fortlaufenden Commentar_, in three parts, 1828, 1836 and 1840) won the highest praise from men like De Wette and Fr. Delitzsch. This work was abridged by Bleek for his college lectures, and was published in that condensed form in 1868. In 1846 he published his contributions to the criticism of the gospels (_Beitrage zur Evangelien Kritik_, pt. i.), which contained his defence of St John's gospel, and arose out of a review of J.H.A. Ebrard's _Wissenschaftliche Kritik der Evangelischen Geschichte_ (1842).

After his death were published:--(1) His _Introduction to the Old Testament_ (_Einleitung in das Alte Testament_), (3rd ed., 1869); Eng.

trans. by G.H. Venables (from 2nd ed., 1869); in 1878 a new edition (the 4th) appeared under the editorship of J. Wellhausen, who made extensive alterations and additions; (2) his _Introduction to the New Testament_ (3rd ed., W. Mangold, 1875), Eng. trans. (from 2nd German ed.) by William Urwick (1869, 1870); (3) his _Exposition of the First Three Gospels_ (_Synoptische Erklarung der drei ersten Evangelien_), by H. Holtzmann (1862); (4) his _Lectures on the Apocalypse_ (_Vorlesungen uber die Apokalypse_), (Eng. trans. 1875). Besides these there has also appeared a small volume containing _Lectures on Colossians, Philemon and Ephesians_ (Berlin, 1865). Bleek also contributed many articles to the _Studien und Kritiken_. For further information as to Bleek's life and writings, see Kamphausen's article in Herzog-Hauck, _Realencyklopadie_; Frederic Lichtenberger's _Histoire des idees religieuses en Allemagne_, vol. iii.; Diestel's _Geschichte des Allen Testamentes_ (1869); and T.K. Cheyne's _Founders of Old Testament Criticism_ (1893).

BLEEK, WILHELM HEINRICH IMMANUEL (1827-1875), German philologist, son of Friedrich Bleek, was born in 1827 at Berlin. He studied first at Bonn and afterwards at Berlin, where his attention was directed towards the philological peculiarities of the South African languages. In his doctor's dissertation (Bonn, 1851), _De nominum generibus linguarum Africae Australis_, he endeavoured to show that the Hottentot language was of North African descent. In 1854 his health prevented him accompanying Dr W.B. Baikie in the expedition to the Niger; but in the following year he accompanied Bishop Colenso to Natal, and was enabled to prosecute his researches into the language and customs of the Kaffirs. Towards the close of 1856 he settled at Cape Town, and in 1857 was appointed interpreter by Sir George Grey. In 1859 he was compelled by ill health to visit Europe, and on his return in the following year he was made librarian of the valuable collection of books presented to the colony by Sir George Grey. In 1869 he visited England, where the value of his services was recognized by a pension from the civil list.

He died at Cape Town on the 17th of August 1875. His works, which are of considerable importance for African and Australian philology, consist of the _Vocabulary of the Mozambique Language_ (London, 1856); _Handbook of African, Australian and Polynesian Philology_ (Cape Town and London, 3 vols., 1858-1863); _Comparative Grammar of, the South African Languages_ (vol. i., London, 1869); _Reynard the Fox in South Africa, or Hottentot Fables and Tales_ (London, 1864); _Origin of Language_ (London, 1869).

BLENDE, or SPHALERITE, a naturally occurring zinc sulphide, ZnS, and an important ore of zinc. The name blende was used by G. Agricola in 1546, and is from the German _blenden_, to blind, or deceive, because the mineral resembles lead ore in appearance but contains no lead, and was consequently often rejected as worthless. Sphalerite, introduced by E.F.

Glocker in 1847, has the same meaning ([Greek: sphaleros], deceptive), and so have the miners' terms "mock ore," "false lead," and "blackjack."

The term "blende" was at one time used in a generic sense, and as such enters into the construction of several old names of German origin; the species under consideration is therefore sometimes distinguished as zinc-blende.

[Ill.u.s.tration: Fig. 1. ]

Crystals of blende belong to that subcla.s.s of the cubic system in which there are six planes of symmetry parallel to the faces of the rhombic dodecahedron and none parallel to the cubic faces; in other words, the crystals are cubic with inclined hemihedrism, and have no centre of symmetry. The fundamental form is the tetrahedron. Fig. 1 shows a combination of two tetrahedra, in which the four faces of one tetrahedron are larger than the four faces of the other: further, the two sets of faces differ in surface characters, those of one set being dull and striated, whilst those of the other set are bright and smooth.

A common form, shown in fig. 2, is a combination of the rhombic dodecahedron with a three-faced tetrahedron y (311); the six faces meeting in each triad axis are often rounded together into low conical forms. The crystals are frequently twinned, the twin-axis coinciding with a triad axis; a rhombic dodecahedron so twinned (fig. 3) has no re-entrant angles. An important character of blende is the perfect dodecahedral cleavage, there being six directions of cleavage parallel to the faces of the rhombic dodecahedron, and angles between which are 60.

When chemically pure, which is rarely the case, blende is colourless and transparent; usually, however, the mineral is yellow, brown or black, and often opaque, the depth of colour and degree of transparency depending on the amount of iron present. The streak, or colour of the powder, is brownish or light yellow, rarely white. The l.u.s.tre is resinous to adamantine, and the index of refraction high (2.369 for sodium light). The substance is usually optically isotropic, though sometimes it exhibits anomalous double refraction; fibrous zinc sulphide which is doubly refracting is to be referred to the hexagonal species wurtzite. The specific gravity is 4.0, and the hardness 4. Crystals exhibit pyroelectrical characters, since they possess four uniterminal triad axes of symmetry.

[Ill.u.s.tration: FIG. 2.]

[Ill.u.s.tration: FIG. 3.]

Crystals of blende are of very common occurrence, but owing to twinning and distortion and curvature of the faces, they are often rather complex and difficult to decipher. For this reason the mineral is not always readily recognized by inspection, though the perfect dodecahedral cleavage, the adamantine l.u.s.tre, and the brown streak are characters which may be relied upon. The mineral is also frequently found ma.s.sive, with a coa.r.s.e or fine granular structure and a crystalline fracture; sometimes it occurs as a soft, white, amorphous deposit resembling artificially precipitated zinc sulphide. A compact variety of a pale liver-brown colour and forming concentric layers with a reniform surface is known in Germany as _Schalenblende_ or _Leberblende_.

A few varieties of blende are distinguished by special names, these varieties depending on differences in colour and chemical composition. A pure white blende from Franklin in New Jersey is known as cleiophane; snow-white crystals are also found at Nordmark in Vermland, Sweden.

Black blende containing ferrous sulphide, in amounts up to 15 or 20% isomorphously replacing zinc sulphide, is known as marmat.i.te (from Marmato near Guayabal in Colombia, South America) and christophite (from St Christophe mine at Breitenbrunn near Eibenstock in Saxony).

Transparent blende of a red or reddish-brown colour, such as that found near Holywell in Flintshire, is known as "ruby-blende" or "ruby-zinc."

Pribramite is the name given to a cadmiferous blende from Pribram in Bohemia. Other varieties contain small amounts of mercury, tin, manganese or thallium. The elements gallium and indium were discovered in blende.

Blende occurs in metalliferous veins, often in a.s.sociation with galena, also with chalcopyrite, barytes, fluorspar, &c. In ore-deposits containing both lead and zinc, such as those filling cavities in the limestones of the north of England and of Missouri, the galena is usually found in the upper part of the deposit, the blende not being reached until the deeper parts are worked. Blende is also found sporadically in sedimentary rocks; for example, in nodules of clay-ironstone in the Coal Measures, in the cement-doggers of the Lias, and in the casts of fossil sh.e.l.ls. It has occasionally been found on the old timbers of mines. In these cases the zinc sulphide has probably arisen from the reduction of sulphate by organic matter.

Localities for fine crystallized specimens are numerous. Mention may be made of the brilliant black crystals from Alston Moor in c.u.mberland, St Agnes in Cornwall and Derbyshire. Yellow crystals are found at Kapnik-Banya, near Nagy-Banya in Hungary. Transparent yellow cleavage ma.s.ses of large size occur in limestone in the zinc mines at Picos de Europa in the province of Santander, Spain. Beautiful isolated tetrahedra of transparent yellow blende are found in the snow-white crystalline dolomite of the Binnenthal in the Valais, Switzerland.

(L. J. S.)

BLENHEIM (Ger. _Blindheim_), a village of Bavaria, Germany, in the district of Swabia, on the left bank of the Danube, 30 m. N.E. from Ulm by rail, a few miles below Hochstadt. Pop. 700. It was the scene of the defeat of the French and Bavarians under Marshals Tallard and Marsin, on the 13th of August 1704, by the English and the Austrians under the duke of Marlborough and Prince Eugene. In consideration of his military services and especially his decisive victory, a princely mansion was erected by parliament for the duke of Marlborough near Woodstock in Oxfordshire, England, and was named Blenheim Palace after this place.

The battle of Blenheim is also called Hochstadt, but the t.i.tle accepted in England has the advantage that it distinguishes this battle from that won on the same ground a year previously, by the elector of Bavaria over the imperial general Styrum (9-20 September 1703), and from the fighting between the Austrians under Krag and the French under Moreau in June 1800 (see FRENCH REVOLUTIONARY WARS). The ground between the hills and the marshy valley of the Danube forms a defile through which the main road from Donauworth led to Ulm; parallel streams divide the narrow plain into strips. On one of these streams, the Nebel, the French and Bavarians (somewhat superior in numbers) took up their position facing eastward, their right flank resting on the Danube, their left in the under-features of the hilly ground, and their front covered by the Nebel, on which were the villages of Oberglau, Unterglau and Blenheim.

The imperialist army of Eugene and the allies under Marlborough (52,000 strong) encamped 5 m. to the eastward along another stream, their flanks similarly protected. On the 2nd-13th of August 1704 Eugene and Marlborough set their forces in motion towards the hostile camps; several streams had to be crossed on the march, and it was seven o'clock (five hours after moving off) when the British of Marlborough's left wing, next the Danube, deployed opposite Blenheim, which Tallard thereupon garrisoned with a large force of his best infantry, aided by a battery of 24-pounder guns. The French and Bavarians were taken somewhat by surprise, and were arrayed in two separate armies, each with its cavalry on the wings and its foot in the centre. Thus the centre of the combined forces consisted of the cavalry of Marsin's right and of Tallard's left.

Here was the only good ground for mounted troops, and Marlborough followed Tallard's example when forming up to attack, but it resulted from the dispositions of the French marshal that this weak point of junction of his two armies was exactly that at which decisive action was to be expected. Tallard therefore had a few horse on his right between the Danube and Blenheim, a ma.s.s of infantry in his centre at Blenheim itself, and a long line of cavalry supported by a few battalions forming his left wing in the plain, and connecting with the right of Marsin's army. This army was similarly drawn up. The cavalry right wing was in the open, the French infantry near Oberglau, which was strongly held, the Bavarian infantry next on the left, and finally the Bavarian cavalry with a force of foot on the extreme left in the hills. The elector of Bavaria commanded his own troops in person. Marlborough and Eugene on their part were to attack respectively Tallard and Marsin. The right wing under Eugene had to make a difficult march over broken ground before it could form up for battle, and Marlborough waited, with his army in order of battle between Unterglau and Blenheim, until his colleague should be ready. At 12.30 the battle opened. Lord Cutts, with a detachment of Marlborough's left wing, attacked Blenheim with the utmost fury. A third of the leading brigade (British) was killed and wounded in the vain attempt to break through the strong defences of the village, and some French squadrons charged upon it as it retired; a colour was captured in the _melee_, but a Hessian brigade in second line drove back the cavalry and retook the colour. After the repulse of these squadrons, in which some British cavalry from the centre took part, Cutts again moved forward. The second attack, though pressed even more fiercely, fared no better than the first, and the losses were heavier than before. The duke then ordered Cutts to observe the enemy in Blenheim, and concentrated all his attention on the centre. Here, between Unterglau and Blenheim, preparations were being made, under cover of artillery, for the crossing of the Nebel, and farther up-stream a corps was sent to attack Oberglau. This attack failed completely, and it was not until Marlborough himself, with fresh battalions, drove the French back into Oberglau that the allies were free to cross the Nebel.

In the meanwhile the first line of Marlborough's infantry had crossed lower down, and the first line of cavalry, following them across, had been somewhat severely handled by Tallard's cavalry. The squadrons under the Prussian general Bothmar, however, made a dashing charge, and achieved considerable temporary success. Eugene was now closely engaged with the elector of Bavaria, and both sides were losing heavily. But Eugene carried out his holding attack successfully. Marsin dared not reinforce Tallard to any extent, and the duke was preparing for the grand attack. His whole force, except the detachment of Cutts, was now across the Nebel, and he had formed it in several lines with the cavalry in front. Marlborough himself led the cavalry; the French squadrons received the attack at the halt, and were soon broken. Marsin's right swung back towards its own army. Those squadrons of Tallard's left which retained their order fell back towards the Danube, and a great gap was opened in the centre of the defence, through which the victorious squadrons poured. Wheeling to their left the pursuers drove hundreds of fugitives into the Danube, and Eugene was now pressing the army of Marsin towards Marlborough, who re-formed and faced northward to cut off its retreat. Tallard was already a prisoner, but in the dusk and confusion Marsin slipped through between the duke and Eugene. General Churchill, Marlborough's brother, had meanwhile surrounded the French garrison of Blenheim; and after one or two attempts to break out, twenty-four battalions of infantry and four regiments of dragoons, many of them the finest of the French army, surrendered.

The losses of the allies are stated at 4500 killed and 7500 wounded (British 670 killed and 1500 wounded). Of the French and Bavarians 11,000 men, 100 guns and 200 colours and standards were taken; besides the killed and wounded, the numbers of which vere large but uncertain--many were drowned in the Danube. Marsin's army, though it lost heavily, was drawn off in good order; Tallard's was almost annihilated.

BLENNERHa.s.sETT, HARMAN (1765-1831), Irish-American lawyer, son of an Irish country gentleman of English stock settled in Co. Kerry, was born on the 8th of October 1765. He was educated at Trinity College, Dublin, and in 1790 was called to the Irish bar. After living for several years on the continent, he married in 1796 his niece, Margaret Agnew, daughter of Robert Agnew, the lieutenant-governor of the Isle of Man. Ostracised by their families for this step the couple decided to settle in America, where Blennerha.s.sett in 1798 bought an island in the Ohio river about 2 m. below Parkersburg, West Virginia. Here in 1805 he received a visit from Aaron Burr (q.v.), in whose conspiracy he became interested, furnishing liberal funds for its support, and offering the use of his island as a rendezvous for the gathering of arms and supplies and the training of volunteers. When the conspiracy collapsed, the mansion and island were occupied and plundered by the Virginia militia.

Blennerha.s.sett fled, was twice arrested and remained a prisoner until after Burr's release. The island was then abandoned, and Blennerha.s.sett was in turn a cotton planter in Mississippi, and a lawyer (1819-1822) in Montreal, Canada. After returning to Ireland, he died in the island of Guernsey on the 2nd of February 1831. His wife, who had considerable literary talent and who published _The Deserted Isle_ (1822) and _The Widow of the Rock and Other Poems_ (1824), returned to the United States in 1840, and died soon afterward in New York City while attempting to obtain through Congress payment for property destroyed on the island.