Chapter VIII: Part 8

After the Restoration, and after a brief period of experiment with rhymed plays, the dramatists returned to the use of blank verse, and in the hands of Otway, Lee and Dryden, it recovered much of its magnificence. In the 18th century, Thomson and others made use of a very regular and somewhat monotonous form of blank verse for descriptive and didactic poems, of which the _Night Thoughts_ of Young is, from a metrical point of view, the most interesting. With these poets the form is little open to licence, while inversions and breaks are avoided as much as possible. Since the 18th century, blank verse has been subjected to constant revision in the hands of Wordsworth, Coleridge, Shelley, Keats, Tennyson, the Brownings and Swinburne, but no radical changes, of a nature unknown to Shakespeare and Milton, have been introduced into it.

See J.A. Symonds, _Blank Verse_ (1895); Walter Thomas, _Le Decasyllabe
romain et sa fortune en Europe_ (1904); Robert Bridges _Milton's
Prosody_ (1894); Ed. Guest, _A History of English Rhythms_ (1882); J.
Mothere, _Les Theories du vers hereoique anglais_ (1886); J. Schipper,
_Englische Metrik_ (1881-1888). (E. G.)

BLANQUI, JEROME ADOLPHE (1798-1854), French economist, was born at Nice on the 21st of November 1798. Beginning life as a schoolmaster in Paris, he was attracted to the study of economics by the lectures of J.B. Say, whose pupil and assistant he became. Upon the recommendation of Say he was in 1825 appointed professor of industrial economy and of history at the Conservatoire des Arts et Metiers. In 1833 he succeeded Say as professor of political economy at the same institution, and in 1838 was elected a member of the Academie des Sciences Morales et Politiques. In 1838 appeared his most important work, _Histoire de l'economie politique en Europe, depuis les anciens jusqu'a nos jours_. He was indefatigable in research, and for the purposes of his economic inquiries travelled over almost the whole of Europe and visited Algeria and the East. He contributed much to our knowledge of the conditions of the working-classes, especially in France. Other works of Blanqui were _De la situation economique et morale de l'Espagne en 1846; Resume de l'histoire du commerce et de l'industrie_ (1826); _Precis elementaire d'economie politique_ (1826); _Les Classes ouvrieres en France_ (1848).

BLANQUI, LOUIS AUGUSTE (1805-1881), French publicist, was born on the 8th of February 1805 at Puget-Theniers, where his father, Jean Dominique Blanqui, was at that time sub-prefect. He studied both law and medicine, but found his real vocation in politics, and at once constituted himself a champion of the most advanced opinions. He took an active part in the revolution of July 1830, and continuing to maintain the doctrine of republicanism during the reign of Louis Philippe, was condemned to repeated terms of imprisonment. Implicated in the armed outbreak of the Societe des Saisons, of which he was a leading spirit, he was in the following year, 1840, condemned to death, a sentence that was afterwards commuted to imprisonment for life. He was released by the revolution of 1848, only to resume his attacks on existing institutions. The revolution, he declared, was a mere change of name. The violence of the _Societe republicaine centrale_, which was founded by Blanqui to demand a modification of the government, brought him into conflict with the more moderate Republicans, and in 1849 he was condemned to ten years' imprisonment. In 1865, while serving a further term of imprisonment under the Empire, he contrived to escape, and henceforth continued his propaganda against the government from abroad, until the general amnesty of 1869 enabled him to return to France. Blanqui's leaning towards violent measures was illustrated in 1870 by two unsuccessful armed demonstrations: one on the 12th of January at the funeral of Victor Noir, the journalist shot by Pierre Bonaparte; the other on the 14th of August, when he led an attempt to seize some guns at a barrack. Upon the fall of the Empire, through the revolution of the 4th of September, Blanqui established the club and journal _La patrie en danger_. He was one of the band that for a moment seized the reins of power on the 31st of October, and for his share in that outbreak he was again condemned to death on the 17th of March of the following year. A few days afterwards the insurrection which established the Commune broke out, and Blanqui was elected a member of the insurgent government, but his detention in prison prevented him from taking an active part. Nevertheless he was in 1872 condemned along with the other members of the Commune to transportation; but on account of his broken health this sentence was commuted to one of imprisonment. In 1879 he was elected a deputy for Bordeaux; although the election was pronounced invalid, Blanqui was set at liberty, and at once resumed his work of agitation. At the end of 1880, after a speech at a revolutionary meeting in Paris, he was struck down by apoplexy, and expired on the 1st of January 1881. Blanqui's uncompromising communism, and his determination to enforce it by violence, necessarily brought him into conflict with every French government, and half his life was spent in prison. Besides his innumerable contributions to journalism, he published an astronomical work entitled _L'Eternite par les astres_ (1872), and after his death his writings on economic and social questions were collected under the title of _Critique sociale_ (1885).

A biography by G. Geffroy, _L'Enferme_ (1897), is highly coloured and
decidedly partisan.

BLANTYRE, the chief town of the Nyasaland protectorate, British Central Africa. It is situated about 3000 ft. above the sea in the Shire Highlands 300 m. by river and rail N.N.W. of the Chinde mouth of the Zambezi. Pop. about 6000 natives and 100 whites. It is the headquarters of the principal trading firms and missionary societies in the protectorate. It is also a station on the African trans-continental telegraph line. The chief building is the Church of Scotland church, a fine red brick building, a mixture of Norman and Byzantine styles, with lofty turrets and white domes. It stands in a large open space and is approached by an avenue of cypresses and eucalyptus. The church was built entirely by native labour. Blantyre was founded in 1876 by Scottish missionaries, and is named after the birthplace of David Livingstone.

BLANTYRE (Gaelic, "the warm retreat"), a parish of Lanarkshire, Scotland. Pop. (1901) 14,145. The parish lies a few miles south-east of Glasgow, and contains High Blantyre (pop. 2521), Blantyre Works (or Low Blantyre), Stonefield and several villages. The whole district is rich in coal, the mining of which is extensively carried on. Blantyre Works (pop. 1683) was the birthplace of David Livingstone (1813-1873) and his brother Charles (1821-1873), who as lads were both employed as piecers in a local cotton-mill. The scanty remains of Blantyre Priory, founded towards the close of the 13th century, stand on the left bank of the Clyde, almost opposite the beautiful ruins of Bothwell Castle. High Blantyre and Blantyre Works are connected with Glasgow by the Caledonian railway. Stonefield (pop. 7288), the most populous place in the parish, entirely occupied with mining, lies between High Blantyre and Blantyre Works, Calderwood Castle on Rotten Calder Water, near High Blantyre, is situated amid picturesque scenery.

BLARNEY, a small town of Co. Cork, Ireland, in the mid parliamentary division, 5 m. N.W. of the city of Cork on the Cork & Muskerry light railway. Pop. (1901) 928. There is a large manufacture of tweed. The name "blarney" has passed into the language to denote a peculiar kind of persuasive eloquence, alleged to be characteristic of the natives of Ireland. The "Blarney Stone," the kissing of which is said to confer this faculty, is pointed out within the castle. The origin of this belief is not known. The castle, built c. 1446 by Cormac McCarthy, was of immense strength, and parts of its walls are as much as 18 ft. thick. To its founder is traced by some the origin of the term "blarney," since he delayed by persuasion and promises the surrender of the castle to the lord president. Richard Millikin's song, "The Groves of Blarney" (c. 1798), contributed to the fame of the castle, which is also bound up with the civil history of the county and the War of the Great Rebellion.

BLASHFIELD, EDWIN HOWLAND (1848- ), American artist, was born on the 15th of December 1848 in New York City. He was a pupil of Bonnat in Paris, and became (1888) a member of the National Academy of Design in New York. For some years a genre painter, he later turned to decorative work, marked by rare delicacy and beauty of colouring. He painted mural decorations for a dome in the manufacturers' building at the Chicago Exposition of 1893; for the dome of the Congressional library, Washington; for the capitol at St Paul, Minnesota; for the Baltimore court-house; in New York City for the Appellate court house, the grand ball-room of the Waldorf-Astoria hotel, the Lawyers' club, and the residences of W.K. Vanderbilt and Collis P. Huntington; and in Philadelphia for the residence of George W. Drexel. With his wife he wrote _Italian Cities_ (1900) and edited Vasari's _Lives of the Painters_ (1896), and was well known as a lecturer and writer on art. He became president of the Society of Mural Painters, and of the Society of American Artists.

BLASIUS (or BLAISE), SAINT, bishop of Sebaste or Sivas in Asia Minor, martyred under Diocletian on the 3rd of February 316. The Roman Catholic Church holds his festival on the 3rd of February, the Orthodox Eastern Church on the 11th. His flesh is said to have been torn with woolcombers' irons before he was beheaded, and this seems to be the only reason why he has always been regarded as the patron saint of woolcombers. In pre-Reformation England St Blaise was a very popular saint, and the council of Oxford in 1222 forbade all work on his festival. Owing to a miracle which he is alleged to have worked on a child suffering from a throat affection, who was brought to him on his way to execution, St Blaise's aid has always been held potent in throat and lung diseases. The woolcombers of England still celebrate St Blaise's day with a procession and general festivities. He forms one of a group of fourteen (i.e. twice seven) saints, who for their help in time of need have been associated as objects of particularly devoted worship in Roman Catholic Germany since the middle of the 15th century.

See William Hone, _Every Day Book_, i. 210.

BLASPHEMY (through the Fr. from Gr. [Greek: blasphaemia], profane language, slander, probably derived from root of [Greek: blaptein], to injure, and [Greek: phaemae], speech), literally, defamation or evil speaking, but more peculiarly restricted to an indignity offered to the Deity by words or writing. By the Mosaic law death by stoning was the punishment for blasphemy (Lev. xxiv. 16). The 77th Novel of Justinian assigned death as the penalty, as did also the Capitularies. The common law of England treats blasphemy as an indictable offence. All blasphemies against God, as denying His being, or providence, all contumelious reproaches of Jesus Christ, all profane scoffing at the Holy Scriptures, or exposing any part thereof to contempt or ridicule, are punishable by the temporal courts with fine, imprisonment and also infamous corporal punishment. An act of Edward VI. (1547; repealed 1553 and revived 1558) enacts that persons reviling the sacrament of the Lord's Supper, by contemptuous words or otherwise, shall suffer imprisonment. Persons denying the Trinity were deprived of the benefit of the Act of Toleration by an act of 1688. An act of 1697-1698, commonly called the Blasphemy Act, enacts that if any person, educated in or having made profession of the Christian religion, should by writing, preaching, teaching or advised speaking, deny any one of the Persons of the Holy Trinity to be God, or should assert or maintain that there are more gods than one, or should deny the Christian religion to be true, or the Holy Scriptures to be of divine authority, he should, upon the first offence, be rendered incapable of holding any office or place of trust, and for the second incapable of bringing any action, of being guardian or executor, or of taking a legacy or deed of gift, and should suffer three years' imprisonment without bail. It has been held that a person offending under the statute is also indictable at common law (_Rex_ v. _Carlisle_, 1819, where Mr Justice Best remarks, "In the age of toleration, when that statute passed, neither churchmen nor sectarians wished to protect in their infidelity those who disbelieved the Holy Scriptures"). An act of 1812-1813 excepts from these enactments "persons denying as therein mentioned respecting the Holy Trinity," but otherwise the common and the statute law on the subject remain as stated. In the case of _Rex_ v. _Woolston_ (1728) the court declared that they would not suffer it to be debated whether to write against Christianity in _general_ was not an offence punishable in the temporal courts at common law, but they did not intend to include disputes between learned men on _particular_ controverted points.

The law against blasphemy has practically ceased to be put in active operation. In 1841 Edward Moxon was found guilty of the publication of a blasphemous libel (Shelley's _Queen Mab_), the prosecution having been instituted by Henry Hetherington, who had previously been condemned to four months' imprisonment for a similar offence, and wished to test the law under which he was punished. In the case of _Cowan_ v. _Milbourn_ (1867) the defendant had broken his contract to let a lecture-room to the plaintiff, on discovering that the intended lectures were to maintain that "the character of Christ is defective, and his teaching misleading, and that the Bible is no more inspired than any other book," and the court of exchequer held that the publication of such doctrine was blasphemy, and the contract therefore illegal. On that occasion the court reaffirmed the dictum of Chief Justice Hale, that Christianity is part of the laws of England. The commissioners on criminal law (sixth report) remark that "although the law forbids _all_ denial of the being and providence of God or the Christian religion, it is only when irreligion assumes the form of an insult to God and man that the interference of the criminal law has taken place." In England the last prominent prosecution for blasphemy was the case of _R._ v. _Ramsey & Foote_, 1883, 48 L.T. 739, when the editor, publisher and printer of the _Freethinker_ were sentenced to imprisonment; but police court proceedings were taken as late as 1908 against an obscure Hyde Park orator who had become a public nuisance.

Profane cursing and swearing is made punishable by the Profane Oaths Act 1745, which directs the offender to be brought before a justice of the peace, and fined five shillings, two shillings or one shilling, according as he is a gentleman, below the rank of gentleman, or a common labourer, soldier, &c.

By the law of Scotland, as it originally stood, the punishment of blasphemy was death, but by an act of 1825, amended in 1837, blasphemy was made punishable by fine or imprisonment or both.

In France, blasphemy (which included, also, speaking against the Holy Virgin and the saints, denying one's faith, or speaking with impiety of holy things) was from very early times punished with great severity. The punishment was death in various forms, burning alive, mutilation, torture or corporal punishment. In the United States the common law of England was largely followed, and in most of the states, also, statutes were enacted against the offence, but, as in England, the law is practically never put in force. In Germany, the punishment for blasphemy is imprisonment varying from one day to three years, according to the gravity of the offence. To constitute the offence, the blasphemy must be uttered in public, be offensive in character, and have wounded the religious susceptibilities of some other person. In Austria, whoever commits blasphemy by speech or writing is liable to imprisonment for any term from six months up to ten years, according to the seriousness of the offence.

BLASS, FRIEDRICH (1843-1907), German classical scholar, was born on the 22nd of January 1843 at Osnabruck. After studying at Gottingen and Bonn from 1860 to 1863, he lectured at several gymnasia and at the university of Konigsberg. In 1876 he was appointed extraordinary professor of classical philology at Kiel, and ordinary professor in 1881. In 1892 he accepted a professorship at Halle, where he died on the 5th of March 1907. He frequently visited England, and was intimately acquainted with leading British scholars. He received an honorary degree from Dublin University in 1892, and his readiness to place the results of his labours at the disposal of others, together with the courtesy and kindliness of his disposition, won the respect of all who knew him. Blass is chiefly known for his works in connexion with the study of Greek oratory: _Die griechische Beredsamkeit von Alexander bis auf Augustus_ (1865); _Die attische Beredsamkeit_ (1868-1880; 2nd ed., 1887-1898), his greatest work; editions for the Teubner series of Andocides (1880), Antiphon (1881), Hypereides (1881, 1894), Demosthenes (Dindorf's ed., 1885), Isocrates (1886), Dinarchus (1888), Demosthenes (Rehdantz' ed., 1893), Aeschines (1896), Lycurgus, _Leocrates_ (1902); _Die Rhythmen der attischen Kunstprosa_ (1901); _Die Rhythmen der asianischen und romischen Kunstprosa_ (1905). Among his other works are editions of Eudoxus of Cnidus (1887), the [Greek: Athaenaion politeia] (4th ed., 1903), a work of great importance, and Bacchylides (3rd. ed., 1904); _Grammatik des neutestamentlichen Griechisch_ (1902; Eng. trans, by H. St John Thackeray, 1905); _Hermeneutik und Kritik and Palaographie, Buchwesen, und Handschriftenkunde_ (vol. i. of Muller's _Handbuch der klassischen Altertumswissenschaft_, 1891); _Uber die Aussprache des Griechischen_ (1888; Eng. trans, by W.J. Purton, 1890); _Die Interpolationen in der Odyssee_ (1904); contributions to Collitz's _Sammlung der griechischen Dialektinschriften_; editions of the texts of certain portions of the New Testament (Gospels and _Acts_). His last work was an edition of the _Choephori_ (1906).

See notices in the _Academy_, March 16, 1907 (J.P. Mahaffy);
_Classical Review_, May 1907 (J.E. Sandys), which contains also a
review of _Die Rhythmen der asianischen und romischen Kunstprosa_.

BLASTING, the process of rending or breaking apart a solid body, such as rock, by exploding within it or in contact with it some explosive substance. The explosion is accompanied by the sudden development of gas at a high temperature and under a tension sufficiently great to overcome the resistance of the enclosing body, which is thus shattered and disintegrated. Before the introduction of explosives, rock was laboriously excavated by hammer and chisel, or by the ancient process of "fire-setting," i.e. building a fire against the rock, which, on cooling, splits and flakes off. To hasten disintegration, water was often applied to the heated rock, the loosened portion being afterwards removed by pick or hammer and wedge. In modern times blasting has become a necessity for the excavation of rock and other hard material, as in open surface cuts, quarrying, tunnelling, shaft-sinking and mining operations in general.

For blasting, a hole is generally drilled to receive the charge of explosive. The depth and diameter of the hole and the quantity of explosive used are all variable, depending on the character of the rock and of the explosive, the shape of the mass to be blasted, the presence or absence of cracks or fissures, and the position of the hole with respect to the free surface of the rock. The shock of a blast produces impulsive waves acting radially in all directions, the force being greatest at the centre of explosion and varying inversely as the square of the distance from the charge. This is evidenced by the observed facts. Immediately surrounding the explosive, the rock is often finely splintered and crushed. Beyond this is a zone in which it is completely broken and displaced or projected, leaving an enveloping mass of more or less ragged fractured rock only partially loosened. Lastly, the diminishing waves produce vibrations which are transmitted to considerable distances. Theoretically, if a charge of explosive be fired in a solid material of perfectly homogeneous texture and at a proper distance from the free surface, a conical mass will be blown out to the full depth of the drill hole, leaving a funnel-shaped cavity. No rock, however, is of uniform mineralogical and physical character, so that in practice there is only a rough approximation to the conical crater, even under the most favourable conditions. Generally, the shape of the mass blasted out is extremely irregular, because of the variable texture of the rock and the presence of cracks, fissures and cleavage planes. The ultimate or resultant useful effect of the explosion of a confined charge is in the direction where the least resistance is presented. In the actual work of rock excavation it is only by trial, or by deductions based on experience, that the behaviour of a given rock can be determined and the quantity of explosive required properly proportioned.

Blasting, as usually carried on, comprises several operations: (1) drilling holes in the rock to be blasted; (2) placing in the hole the charge of explosive, with its fuze; (3) tamping the charge, i.e. compacting it and filling the remainder of the hole with some suitable material for preventing the charge from blowing out without breaking the ground; (4) igniting or detonating the charge; (5) clearing away the broken material. The holes for blasting are made either by hand, with hammer and drill or jumper, or by machine drill, the latter being driven by steam, compressed air, or electricity, or, in rare cases, by hydraulic power. Drill holes ordinarily vary in diameter from 1 to 3 in., and in depth from a few inches up to 15 or 20 ft. or more. The deeper holes are made only in surface excavation of rock, the shallower, to a maximum depth of say 12 ft., being suitable for tunnelling and mining operations.

_Hand Drilling_.--The work is either "single-hand" or "double-hand."
In single-hand drilling, the miner wields the hammer with one hand,
and with the other holds the drill or "bit," rotating it slightly
after every blow in order to keep the hole round and prevent the drill
from sticking fast; in double-hand work, one man strikes, while the
other holds and rotates the drill. For large and deep holes, two
hammermen are sometimes employed.

A miner's drill is a steel bar, occasionally round but generally of
octagonal cross-section, one end of which is forged out to a cutting
edge (fig. 1). The edge of the drill is made either straight, like
that of a chisel, or with a convex curve, the latter shape being best
for very hard rock. For hard rock the cutting edge should be rather
thicker and blunter, and therefore stronger, than for soft rock.
Drills are made of high-grade steel, as they must be tempered
accurately and uniformly. The diameter of drill steel for hand work is
usually from 3/4 to 1 in., and the length of cutting edge, or gauge,
of the drill is always greater than the diameter of the shank, in the
proportion of from 7.4 to 4.3. Holes over 10 or 12 in. deep generally
require the use of a set of drills of different lengths and depending
in number on the depth required. The shortest drill, for starting the
hole, has the widest cutting edge, the edges of the others being
successively narrower and graduated to follow each other properly, as
drill after drill is dulled in deepening the hole. Thus the hole
decreases in diameter as it is made deeper. The miner's hammer (fig.
2) ranges in weight from 3-1/2 to 4-1/2 lb. for single-hand drilling,
up to 8 or 10 lb. for double-hand. If the hole is directed downward, a
little water is poured into it at intervals, to keep the cutting edge
of the drill cool and make a thin mud of the cuttings. From time to
time the hole is cleaned out by the "scraper" or "spoon," a long
slender iron bar, forged in the shape of a hollow semi-cylinder, with
one end flattened and turned over at right angles. If the hole is
directed steeply upward and the rock is dry, the cuttings will run out
continuously during the drilling; otherwise the scraper is necessary,
or a small pipe with a plunger like a syringe is used for washing out
the cuttings. The "jumper" is a long steel bar, with cutting edges on
one or both ends, which is alternately raised and dropped in the hole
by one or two men. In rock work the jumper is rarely used except for
holes directed steeply downward, though for coal or soft shale or
slate it may be employed for drilling holes horizontally or upward.
Other tools used in connexion with rock-drilling are the pick and gad.

Holes drilled by hand usually vary in depth from say 18 to 36 in.,
according to the nature of the rock and purpose of the work, though
deeper holes are often made. For soft rock, single-hand drilling is
from 20 to 30% cheaper than double-hand, but this difference does not
hold good for the harder rocks. For these double-hand drilling is
preferable, and may even be essential, to secure a reasonable speed of
work.

_Machine Drills._--The introduction of machine drills in the latter
part of the 19th century exerted an important influence on the work of
rock excavation in general, and specially on the art of mining. By
their use many great tunnels and other works involving rock excavation
under adverse conditions have been rapidly and successfully carried
out. Before the invention of machine drills such work progressed
slowly and with difficulty. Nearly all machine drills are of the
reciprocating or percussive type, in which the drill bit is firmly
clamped to the piston rod and delivers a rapid succession of strong
blows on the bottom of the hole. The ordinary compressed air drill
(which may, for surface work, be operated also by steam) may be taken
as an illustration. The piston works in a cylinder, provided with a
valve motion somewhat similar to that of a steam-engine, together with
an automatic device for producing the necessary rotation of the piston
and drill bit. While at work the machine is mounted on a heavy tripod
(fig. 3); or, if underground, sometimes on an iron column or bar,
firmly wedged in position between the roof and floor, or side walls,
of the tunnel or mine working. As the hole is deepened, the entire
drill head is gradually fed forward on its support by a screw feed, a
succession of longer and longer drill bits being used as required.

Among the numerous types and makes of percussion drill may be named
the following:--Adelaide, Climax, Darlington, Dubois-Francois,
Ferroux, Froelich, Hirnant, Ingersoll, Jeffrey, Leyner, McKiernan,
Rand, Schram, Sergeant, Sullivan and Wood.

One of the simplest of the machine drills is the Darlington (figs. 4
and 5): a is the cylinder; b, piston rod; c, bit; d, d, air inlets,
either being used according to the position of the drill while at
work; h, piston; j, rifle-bar for rotating piston and bit; k, ratchet
attached to j; l, brass nut, screwed into h, and in which j works; f,
chuck for holding drill-bit; n, air port communicating between ends of
cylinder, front and back of piston; o, exhaust port. This machine has
no valve. From its construction, the compressed air (or steam) is
always acting on the annular shoulder round the forward end of the
piston. The piston is thereby forced back on the in-stroke until the
port n is uncovered. This admits the compressed air to the rear end of
the cylinder, and as the area of this end of the piston is much
greater than that of the shoulder on the other end, the piston is
driven forward and strikes its blow. When it has advanced far enough
to cover the exhaust port o, the air behind the piston is exhausted,
and, under the constant inward pressure noted above, the stroke is
reversed. The rotation of piston and bit is caused by the rifle-bar j.
On the outward stroke, j, with its ratchet k, is free to turn under a
couple of pawls and springs, and consequently the piston delivers its
blow without rotation. On the inward stroke the ratchet is held fast
by the pawls, and the piston and bit are forced to rotate through a
small part of a revolution. The cylinder is fed forward with respect
to the shell r, by rotating the handle p, which works a long screw-bar
engaging with a nut on the under side of the cylinder. The shell r is
bolted to the clamp s, which in turn is mounted on the hollow column
or bar g, or on a tripod, according to the character of the work. By
means of the adjustable clamp s, the machine can be set for drilling a
hole in any desired direction. The drill makes from 400 to 800 strokes
per minute.

The "New Ingersoll" drill, which may be taken as an example of the
numerous machines in which valves are used, is shown in section in
fig. 6. The steam or compressed air is distributed through the ports
alternately to the ends of the cylinder, by the reciprocations of a
spool-valve working in a chest mounted on the cylinder. The movements
of this valve are caused by the strokes of the main piston, which, by
means of the wide annular groove around the middle of the piston,
alternately open and close the spool-valve exhaust ports. Fig. 3 shows
the Ingersoll "Light Mining drill," as mounted on a tripod, and in
position for drilling a hole vertically downward. In the Leyner drill
the drill-bit is not connected to the piston, but is struck a quick
succession of blows by the latter. An important feature of this
machine is the provision for directing a stream of water into the hole
for clearing out the cuttings. For this purpose the shank of the
drill-bit is perforated longitudinally, the water being supplied under
pressure from a small tank, to which compressed air is led.

A rock drill of entirely different design, the Brandt, has been
successfully used in Europe for driving railway tunnels. It is
operated by hydraulic power, the pressure water being supplied by a
pump. The hollow drill-bit, which has a serrated cutting edge, is
forced under heavy pressure against the bottom of the hole, and is
rotated slowly--at six to eight revolutions per minute--by a pair of
small hydraulic cylinders, thus grinding and crushing the rock instead
of chipping it. The bottom of the hole is kept clean and the drill-bit
cooled by a stream of water passing down through its hollow shank. On
account of its size and weight, this machine is not suitable for mine
work.

Most of the machine drills are made in a number of sizes, from 2 in.
up to 5 in. diameter of cylinder, the larger sizes being capable of
drilling holes 5 in. diameter and 30 ft. deep. They range in weight
from say 95 to 690 lb. for the drill head (unmounted), the tripods
weighing from 40 to 260 lb., exclusive of the weights placed for
stability on the tripod legs (fig. 3). The sizes in most common use
for mining are from 2-1/2 in. to 3-1/8 in. diameter of cylinder. In
rock of average hardness the best drills make from 4 to 7.5 linear ft.
of hole per hour. For use in narrow veins, or other confined workings
underground, several extremely small and light compressed air drills
have been introduced, as, for example, the Franke and Wonder, the
first of which weighs complete only 16 lb., and the second 18 lb.
These drills are held in the hands of the miner in the required
position, and strike a rapid succession of light blows. A large number
of mechanical drills operated by hand power have been invented. Some
imitate hand-drilling in the mode of delivering the blow; in others
the drill-bit is caused to reciprocate by means of combinations of
crank and spring. None of these machines is entirely satisfactory, and
but few are in use.

Among percussion rock-drills operated by electricity are the Bladray,
Box, Durkee, Marvin and Siemens-Halske. The Marvin drill works with a
solenoid; most of the others have crank and spring movements for
producing the reciprocations of the piston. Power is furnished by a
small electric motor, either mounted on the machine itself, as with
the Box drill, or more often standing on the ground and transmitting
its power through a flexible shaft. Although rather frequently used,
electric percussion drills cannot yet be considered entirely
successful, at least for mine service, in competition with compressed
air machines. Another type of electric drill, however, has been
successfully used in collieries, viz. rotary auger drills, mounted on
light columns and driven through gearing by diminutive motors. These
are intended for boring in coal, slate or other similar soft material.
Hand augers resembling a carpenter's brace and bit are also often used
in collieries.

Whatever may be the method of drilling, after the hole has been
completed to the depth required, it is finally cleaned out by a
scraper or swab; or, when compressed air drills are used, by a jet of
air directed into the hole by a short piece of pipe connected through
a flexible hose with the compressed air supply pipe. The hole is then
ready for the charge.

_Location and Arrangement of Holes._--For hand drilling in mining the
position of the holes is determined largely by the character and shape
of the face of rock to be blasted. The miner observes the joints and
cracks of the rock, placing the holes to take advantage of them and so
obtain the best result from the blast. In driving a tunnel or drift,
as in figs. 7 and 8, the rock joints can be made of material
assistance by beginning with hole No. 1 and following in succession by
Nos. 2, 3 and 4. Frequently the ore, or vein matter, is separated from
the wall-rock by a thin, soft layer of clay (D, D, fig. 8). This would
act almost as a free face, and the first holes of the round would be
directed at an angle towards it, for blasting out a wedge; after which
the positions of the other holes would be chosen.

When machine drills are employed, less attention is given to natural
cracks or joints, chiefly because when the drill is once set up
several holes at different angles can be drilled in succession by
merely swinging the cylinder of the machine into a new position with
respect to its mounting. According to one method, the holes are placed
with some degree of symmetry, in roughly concentric rings, as shown by
figs. 9 and 10. The centre holes are blasted first, and are followed
by the others in one or more volleys as indicated by the dotted lines.
Another method is the "centre cut," in which the holes are drilled in
parallel rows on each side of the centre line of the tunnel, drift or
shaft. Those in the two rows nearest the middle are directed towards
each other, and enclose a prism of rock, which is first blasted put by
heavy charges, after which the rows of side holes will break with
relatively light charges.

_Explosives._--A great variety of explosives are in use for blasting
purposes. Up to 1864, gunpowder was the only available explosive, but
in that year Alfred Nobel first applied nitroglycerin for blasting,
and in 1867 invented dynamite. This name was originally applied to his
mixture of nitroglycerin with kieselguhr, but now includes also other
mechanical mixtures or chemical compounds which develop a high
explosive force as compared with gunpowder. Besides these there are
the so-called flameless or safety explosives, used in collieries where
inflammable gases are given off from the coal.

Gunpowder, or black powder, is seldom used for rock-blasting, except
in quarrying building-stone, where slow explosives of relatively low
power are desirable to avoid shattering the stone, and in such
collieries as do not require the use of safety explosives. Gunpowder
is exploded by deflagration, by means of a fuze, and exerts a
comparatively slow and rending force. The high explosives, on the
other hand, are exploded by detonation, through the agency of a fuze
and fulminating cap, exerting a quick, shattering, rather than a
rending force. Dynamites and flameless explosives are made in a
variety of strengths, and are packed in waterproofed cartridges of
different sizes. The grades of dynamite most commonly employed contain
from 35 to 60% of nitroglycerin; the stronger are used for tough rock
or deep holes, or for holes unfavourably placed in narrow mine
workings, as sometimes in shaft-sinking or tunnelling. When of good
quality high explosives are safer to handle than gunpowder, as they
cannot be ignited by sparks and are not so easily exploded. The
ordinary dynamites used in mining are about four times as powerful as
gunpowder.

Nitroglycerin in its liquid form is now rarely used for blasting,
partly because its full strength is not often necessary but chiefly
because of the difficulty and danger of transporting, handling and
charging it. If employed at all, it is charged in thin tinned plate
cases or rubber-cloth cartridges.

_Blasting with Black Powder._--The powder is coarse-grained, usually
from 1/8 to 3/16 in. in size, and is charged in paper cartridges, 8 to
10 in. long and of a proper diameter to fit loosely in the drill hole.
A piece of fuze, long enough to reach a little beyond the mouth of the
hole, is inserted in the cartridge and tied fast. For wet holes
paraffined paper is used, the miner waterproofing the joints with
grease. When more than one cartridge is required for the blast, that
which has the fuze attached is usually charged last. The cartridges
are carefully rammed down by a wooden tamping bar and the remainder of
the hole filled with tamping. This consists of finely broken rock, dry
clay or other comminuted material, carefully compacted by the tamping
bar on top of the charge. The fuze is a cord, having in the centre a
core of gunpowder, enclosed in several layers of linen or hemp
waterproofed covering. It is ignited by the miner's candle or lamp, or
by a candle end so placed at the mouth of the hole that the flame must
burn its way through the fuze covering. As the fuze burns slowly, at
the rate of 2 or 3 ft. per minute, the miner uses a sufficient length
to allow him to reach a place of safety.

For blasting in coal, "squibs" instead of fuzes are often used. A
squib is simply a tiny paper rocket, about 1/8 in. diameter by 3 in.
long, containing fine gunpowder and having a sulphur slow-match at one
end. It is fired into the charge through a channel in the tamping.
This channel may be formed by a piece of 1/4 in. gas pipe, tamped in
the hole and reaching the charge; or a "needle," a long taper iron
rod, is laid longitudinally in the hole, with its point entering the
charge, and after the tamping is finished, by carefully withdrawing
the needle a little channel is left, through which the squib is fired.
In this connexion it may be noted that for breaking ground in gassy
collieries several substitutes for explosives have been used to a
limited extent, e.g. plugs of dry wood driven tightly into a row of
drill holes, and which on being wetted swell and split the coal;
quicklime cartridges, which expand powerfully on the application of
water; simple wedges, driven by hammer into the drill holes; multiple
wedges, inserted in the holes and operated by hydraulic pressure from
a small hand force-pump.

_Blasting with High Explosives._--High explosives are fired either by
ordinary fuze and detonating cap or by electric fuze. Detonating caps
of ordinary strength contain 10 to 15 grains of fulminating mixture.
The cap is crimped tight on the end of the fuze, embedded in the
cartridge, and on being exploded by fire from the fuze detonates the
charge. The number of cartridges charged depends on the depth of hole,
the length of the line of least resistance, and the toughness and
other characteristics of the rock. Each cartridge should be solidly
tamped, and, to avoid waste spaces in the hole, which would reduce the
effect of the blast, it is customary to split the paper covering
lengthwise with a knife. This allows the dynamite to spread under the
pressure of the tamping bar. The cap is often placed in the cartridge
preceding the last one charged, but it is better to insert it last, in
a piece of cartridge called a "primer." Though the dynamites are not
exploded by sparks, they should nevertheless always be handled
carefully. It is not so essential to fill the hole completely and so
thoroughly to compact the tamping, as in charging black powder,
because of the greater rapidity and shattering force of the explosion
of dynamite; tamping, however, should never be omitted, as it
increases the efficiency of the blast. In exploding dynamite, strong
caps, containing say 15 grains of fulminating powder, produce the best
results. Weaker caps are not economical, as they do not produce
complete detonation of the dynamite. This is specially true if the
weather be cold. Dynamite then becomes less sensitive, and the
cartridges should be gently warmed before charging, to a temperature
of not more than 80 deg. F. Poisonous fumes are often produced by the
explosion of the nitroglycerin compounds. These are probably largely
due to incomplete detonation, by which part of the nitroglycerin is
vaporized or merely burned. This is most likely to occur when the
dynamite is chilled, or of poor quality, or when the cap is too weak.
There is generally but little inconvenience from the fumes, except in
confined underground workings, where ventilation is imperfect.

Like nitroglycerin, the common dynamites freeze at a temperature of
from 42 deg. to 46 deg. F. They are then comparatively safe, and so
far as possible should be transported in the frozen state. At very low
temperatures dynamite again becomes somewhat sensitive to shock. When
it is frozen at ordinary temperatures even the strongest detonating
caps fail to develop the full force. In thawing dynamite, care must be
exercised. The fact that a small quantity will often burn quietly has
led to the dangerously mistaken notion that mere heating will not
cause explosion. It is chiefly a question of temperature. If the
quantity ignited by flame be large enough to heat the entire mass to
the detonating point (say 360 deg. F.) before all is consumed, an
explosion will result. Furthermore, dynamite, when even moderately
heated, becomes extremely sensitive to shocks. There are several
accepted modes of thawing dynamite: (1) In a water bath, the
cartridges being placed in a vessel surrounded on the sides and bottom
by warm water contained in a larger enclosing vessel. The warm water
may be renewed from time to time, or the water bath placed over a
candle or small lamp, _not_ on a stove. (2) In two vessels, similar to
the above, with the space between them occupied by air, provided the
heat applied can be definitely limited, as by using a candle. (3) When
large quantities of dynamite are used a supply may be kept on shelves
in a wooden room or chamber, warmed by a stove, or by a coil of pipe
heated by exhaust steam from an engine. Live steam should not be used,
as the heat might become excessive. Thawing should always take place
slowly, never before an open fire or by direct contact with a stove or
steam pipes and care must be taken that the heat does not rise high
enough to cause sweating or exudation of liquid nitroglycerin from the
cartridges, which would be a source of danger.

For the storage of explosives at mines, &c., proper magazines must be
provided, situated in a safe place, not too near other buildings, and
preferably of light though fireproof construction. Masonry magazines,
though safer from some points of view, may be the cause of greater
damage in event of an explosion, because the brick or stones act as
projectiles. Isolated and abandoned mine workings, if dry, are
sometimes used as magazines.

Firing blasts by electricity has a wide application for both surface
and underground work. An electrical fuze (fig. 11) consists of a pair
of fine, insulated copper wires, several feet long and about 1/40 of
an inch in diameter, with their bare ends inserted in a detonating
cap. For firing, the fuze wires are joined to long leading wires,
connected with some source of electric current. By joining the fuze
wires in series or in groups, any number of holes may be fired
simultaneously, according to the current available. A round of holes
fired in this way, as for driving tunnels, sinking shafts, or in large
surface excavations, produces better results, both in economy of
explosive and effect of the blast, than when the holes are fired
singly or in succession. Also, the miners are enabled to prepare for
the blast with more care and deliberation, and then to reach a place
of safety before the current is transmitted. Another advantage is that
there is no danger of a hole "hanging fire," which sometimes causes
accidents in using ordinary fuzes.

Hanging fire may be due to a cut, broken or damaged powder fuze, which
may smoulder for some time before communicating fire to the charge.
"Miss-fires," which also are of not infrequent occurrence with both
ordinary and electric fuzes, are cases where explosion from any cause
fails to take place. After waiting a sufficient length of time before
approaching the charged hole, the miner carefully removes the tamping
down to within a few inches of the explosives and inserts and fires
another cartridge, the concussion usually detonating the entire
charge. Sometimes another hole is drilled near the one which has
missed. No attempt to remove the old charge should ever be made.

High tension electricity, generated by a frictional machine, provided
with a condenser, was formerly much used for blasting. The bare ends
of the fuze wires in the detonating cap are placed say 1/8 in. apart,
leaving a gap across which a spark is discharged, passing through a
priming charge of some sensitive composition. The priming is not only
combustible but also a conductor of electricity, such as an intimate
mixture of potassium chlorate with copper sulphide and phosphide. By
the combustion of the priming the fulminate mixture in the cap is
detonated. As these fuzes are more apt to deteriorate when exposed to
dampness than fuzes for low-tension current, and the generating
machine is rather clumsy and fragile, low-tension current is more
generally employed. It may be generated by a small, portable dynamo,
operated by hand, or may be derived from a battery or from any
convenient electric circuit. The ends of the fuze wires in the
detonating cap are connected by a fine platinum filament (fig. 11),
embedded in a guncotton priming on top of the fulminating mixture, and
explosion results from the heat generated by the resistance opposed to
the passage of the current through the filament. Blasting machines are
made in several sizes, the smaller ones being capable of firing
simultaneously from ten to twenty holes. The fuzes must obviously be
of uniform electrical resistance, to ensure that all the connected
charges will explode simultaneously. The premature explosion of any
one of the fuzes would break the circuit.

In the actual operations of blasting, definite rules for the
proportioning of the charges are rarely observed, and although the
blasts made by a skilful miner seldom fail to do their work, it is a
common fault that too much, rather than too little, explosive is used.
The high explosives are specially liable to be wasted, probably
through lack of appreciation of their power as compared with that of
black powder. Among the indications of excessive charges are the
production of much finely broken rock or of crushed and splintered
rock around the bottom of the hole, and excessive displacement or
projection of the rock broken by the blast. In beginning any new piece
of work, such waste may be avoided or reduced by making trial shots
with different charges and depths of hole, and noting the results;
also by letting contracts under which the workmen pay for the
explosive. In surface rock excavation the location and determination
of the depth of the holes and the quantity of explosive used, are
occasionally put in charge of one or more skilled men, who direct the
work and are responsible for the results obtained.

Blasting in surface excavations and quarries is sometimes done on an
immense scale--called "mammoth blasting." Shafts are sunk, or tunnels
driven, in the mass of rock to be blasted, and, connected with them, a
number of chambers are excavated to receive the charges of explosive.
The preparation for such blasts may occupy months, and many tons of
gunpowder or dynamite are at times exploded simultaneously, breaking
or dislodging thousands, or even hundreds of thousands, of tons of
rock. This method is adopted for getting stone cheaply, as for
building macadamized roads, dams and breakwaters, obtaining limestone
for blast furnace flux, and occasionally in excavating large railway
cuttings. It is also applied in submarine blasting for the removal of
reefs obstructing navigation, and sometimes for loosening extensive
banks of partly cemented gold-bearing gravel, preparatory to washing
by hydraulic mining.

AUTHORITIES.--For further information on drilling and blasting
see:--Callon, _Lectures on Mining_ (1876), vol. i. chs. v. and vi.;
Foster, _Text-book of Ore and Stone Mining_, (1900), ch. iv.; Hughes,
_Text-book of Coal Mining_ (1901), ch. iii.; H.S. Drinker,
_Tunnelling, Explosive Compounds and Rock Drills_ (1878); M.C.
Ihlseng, _Manual of Mining_ (1905), pp. 596-696; Kohler, _Der
Bergbaukunde_ (1897), pp. 104-208; Daw, _The Blasting of Rock_ (1898);
Prelini, _Earth and Rock Excavation_ (1905), chs. v., vi. and vii.;
Gillette, _The Excavation of Rock_ (1904); Guttmann, _Blasting_
(1892); Spon's _Dictionary of Engineering_, art. "Boring and
Blasting"; Eissler, _Modern High Explosives_ (1893), pts. ii. and
iii.; Walke, _Lectures on Explosives_ (1897), chs. xix.-xxii. Also:
_Proc. Inst. Civ. Eng._ (London), vol. lxxxv. p. 264; _Trans. Inst.
Min. Eng._ (England), vols. xiv., xv. and xvi. (arts, by W. Maurice),
vol. xxvi. pp. 322, 348, vol. xxiv. p. 526 and vol. xxv. p. 108;
_Trans. Amer. Soc. Civ. Eng._, vol. xxvii. p. 530; _Trans. Amer. Inst.
Min. Eng._, vol. xviii. p. 370, vol. xxix p. 405 and vol. xxxiv. p.
871; _South Wales Inst. Eng._ (1888); _Jour. Ass. Eng. Socs._, vol.
vii. p. 58; _Jour. Chem. Met. and Mining Soc. of South Africa_, August
1905; _School of Mines Quarterly_, N.Y., vol. ix. p. 308; _Colliery
Guardian_, April 15, 1898, and February 6, 1903; _Mines and Minerals_,
February 1905, p. 348, January 1906, p. 259, and April 1906, p. 393;
_Eng. and Mining Jour._, April 19, 1902, p. 552; _The Engineer_,
February 24, 1905; _Elec. Rev._, June 9, 1899; _Eng. News_, vol.
xxxii. p. 249, and August 3, 1905; _Gluckauf_, September 28, 1901, and
July 5, 1902; _Osterr. Zeitschr. f. Berg- u. Huttenwesen_, May 18, 25,
1901, April 18, 1903 and November, 18, 1905; _Annales des mines_, vol.
xviii. pp. 217-248. (R. P.*)

BLAUBEUREN, a town of Germany, in the kingdom of Wurttemberg, 12 m. W. of Ulm, with which it is connected by railway. Pop. (1900) 3114. It is romantically situated in a wild and deep valley of the Swabian Alps at an altitude of 1600 ft. and is partly surrounded by ancient walls. Of the three churches (two Evangelical and one Roman Catholic) the most remarkable is the abbey church (_Klosterkirche_), a late Gothic building dating from 1465-1496, the choir of which contains beautiful 15th century carved choir-stalls and a fine high altar with a triptych (1496). The choir only is used for service (Protestant), the nave being used as a gymnasium. The town church (_Stadtkirche_) also has a fine altar with triptych. The Benedictine abbey, founded in 1095, was used after the Reformation as a school, and is now an Evangelical theological seminary. There are two hospitals in the town.