Images de page








bola, any ray falling on the mirror parallel to the made of hollow platinum, so arranged that a flame axis is reflected so as to pass exactly through the of benzole can be kept burning in its interior. The focus. For other mirrors it is approximately true galvano-cautery consists essentially of a platinum only when the breadth of the mirror is very small wire which can be heated to any required degree in comparison with its radius of curvature. When by passing a strong, galvanic current through it. the breadth of the mirror is large in comparison The cautery is used for three main purposes in with its radius of curvature there is no definite surgery: to produce counter-irritation over an inimage, even of a luminous point. In such cases flamed part (see BLISTER) (actual cautery); to the image is spread over what is called a Caustic, check bleeding (actual or thermo-cautery), by or sometimes a Catacaustic.

slowly destroying the tissues at the bleeding point An example of the caustic is given in the annexed or surface; to perform operations, where the tissues figure for the simplest case—namely, that of rays to be divided are either very vascular (thermofalling directly on a concave spherical mirror, BAB', cautery), or very difficult of access (galvanofrom a point so distant as to be practically parallel. cautery). See CÂUSTIC.

Two very near rays, Caution, in the Law of Scotland, like Guaranty P and Q, will after (q.v.) in England, is an obligation undertaken by a reflection intersect second party, whereby he binds himself, failing the at C.

By finding primary obligant, to fulfil his obligation, whether in this way all the it be of a pecuniary nature or otherwise. Cautionpoints of intersection

ary obligations are thus essentially of an accessory of the reflected rays, nature, and cannot subsist apart from the principal we get a continuous obligation. The law of this subject is now largely curve, BCFB', which founded on the Mercantile Law Amendment Acts, is the section of the 1856, which assimilate the laws of England and caustic surface by Scotland, and according to which the creditor a plane passing may proceed at once against the cautioner, just through its axis.

as if he were a joint obligant, without suing The curve BCFB' varies of course with the form of the primary debtor, unless the cautioner has the reflecting surface. In the case under considera- expressly stipulated that this shall be done. tion it is known as an epicycloid.

The creditor, however, is in every case bound to The reader may see a catacaustic on the surface of tea in a tea-cup half full by holding the circular available securities. He is not, however, bound

use proper precaution in retaining and making rim to the sun's light. The space within the caustic to make the same full disclosure of material curve is all brighter than that without, as it clearly facts as in insurance, and therefore a cautioner should be, as all the light reflected affects that should make careful inquiry for himself. Cautionspace, while no point without the curve is affected

ary obligations are generally gratuitous, being, by more than the light reflected from half of the for the most part, undertaken from motives of surface. The rainbow, it may be mentioned, forms friendship; but it is by no means uncommon for one of the most interesting of the whole family of them to be entered into in consideration of a caustics.

premium paid by the person guaranteed, or by When a caustic is produced by refraction, it is those interested 'in his fortunes. Where å presometimes called a Diacaustic. No such simple mium is paid, the transaction becomes a mere example can be given of the diacaustic curve as that above given of the catacaustic. It is only in associations of great public utility (see GỦARAN:

insurance of solvency, honesty, or efficiency ; and the simplest cases that the curve takes a recognis- TEE) have been formed, both in England and able form. In the case of refraction at a plane Scotland, for the purpose of undertaking to surface, it can be shown that the diacaustic curve is the evolute either of the hyperbola or ellipse, marantee the fidelity of persons employed either according as the refractive index of the medium is of judicial decisions, both in England and Scotland,

The tendency greater or less than unity.

for many years past, has been to require greater Cauterets, a fashionable French watering- strictness than formerly in the constitution of place in the department of Hautes-Pyrénées, lies cautionary obligations; and under the statutes 3250 feet above sea level, in the valley of the already mentioned all such engagements must be Laverdan, 5 miles S. of Pierrefitte, the nearest

in writing, subscribed by the person undertaking railway station, and 42 SSE. of Pau. The or making them, or by some person duly authorised stationary population was (1886) only 1468, but hy hini, otherwise they shall have no effect. If a it is annually swelled in summer by 15,000 to cautionary obligation is dependent on a condition, 20,000 visitors, for whose accommodation numer

it will, of course, be ineffectual unless the condious sumptuous hotels and bathing-establishments tion be complied with. The cautioner may, in have been built. It is a good centre and guide- general, plead every defence which was competent station for ascents among the Pyrenees. The

to the principal debtor, and the extinction of the sulphurous springs, twenty-five in number, and primary obligation extinguishes the secondary one. varying in temperature from 60° to 131° F., are

The cautioner is discharged by any essential charge the most abundant in the Pyrenees (330,000 gallons being made on the obligation of the debtor, or în per day), and have been known from Roman respect of the person relied on, without his assent. times; though their modern reputation dates from The statute expressly provides that changes of the 16th century, when Margaret, sister of Francis partnership either of creditor or debtor will exI., held her literary court and wrote much of her tinguish the guarantee. If the creditor gives time Heptumeron at Cauterets.

-e.g. takes bills from the debtor of an unusual

currency—that will also operate discharge. The Cautery (Gr. kaio, 'I burn'), in Medicine, is discharge of one cautioner, moreover, unless conused of any substance which burns the tissues. sented to by the rest, is a discharge to all. The (The term "potential cautery,' as applied to caustic cautioner is entitled, on full payment, though not substances, is becoming obsolete.) The actual on payment by a dividend, to an assignation of the cautery is an instrument with a head or blade of debt and diligence, by which means he comes, in steel, iron, or platinum, which is heated in a fire or all respects, into the creditor's place; and more: spirit-lamp. In the thermo-cautery (or Paquelin's over, if the solvency or other conditions of the cautery, from its inventor), the head or blade is principal debtor should seem precarious, he may

[ocr errors]
[ocr errors]
[blocks in formation]
[merged small][ocr errors]

adopt legal measures for his relief. Co-cautioners, to his generalship: His task being done, he or persons bound together, whether their obliga resigned his power into the hands of the National tions be embodied in one or several deeds, are Assembly, which appointed him President of the entitled to mutual relief. But where a co-cautioner Council. As a candidate for the presidency of the obtains relief from the others, he must communicate republic, when Louis Napoleon was elected, he to them the benefit of any deduction or ease which received nearly a million and a half of votes out may have been allowed him in paying the debt. of 7,327,345. On the coup d'état of December 1851,

Letters of credit and recommendation raise much Çavaignac was arrested, but released after a short the same relation of parties as a formal cautionary detention ; and though he consistently refused to obligation, but since 1856 a mere verbal introduc- give in his adhesion to the Empire, he was pertion cannot have that effect. For the forms and mitted to reside in France without molestation. effects of ordinary mercantile guarantees, and for He died, 28th October 1857, at his country house the forms of guarantee insurance of fidelity, see near Tours. Cavaignac. was an able soldier, a GUARANTEE. For the Scottish cautionary obliga- zealous republican, and in every way an honourtion in cash-credit bond, see BANKING, II. 713.

able man. See his Life by Deschamps (2 vols. JUDICIAL CAUTION, in the Law of Scotland, is Paris, 1870). of two kinds-for appearance, and for payment. If Cavaillon (ancient Cabellio), a town of the & creditor makes oath before a magistrate, that he French department of Vaucluse, 18 niles SE. of believes his debtor to be meditating flight (in medi- Avignon by rail, with a cathedral, and some tatione fugæ), he may obtain a warrant for his Roman remains. Pop. 5164. apprehension; and should he succeed in proving the alleged intention to flee, he may compel him

Cavalcanti, GUIDO, Italian poet, born in 1230, to find caution to abide the judgment of a court

was banished, for mercantile transactions with a (judicio sisti). The cautioner, or surety, under- Guelph, by the Ghibellines, a daughter of one of takes that the defender shall appear to answer any broken health to Florence only to die there, about

whose chiefs he had married, and returned in action that may be brought within six months. The old Bond of Presentation, by which in order to

1300. His works —sonnets, ballads, and canzonigain time the surety undertook to produce the

are remarkable alike from their language and depth debtor or pay the debt at a future date, is now

of thought, although his epicurean philosophy superseded by the abolition of imprisonment for gained him, among his contemporaries, the reputadebt. There is also a form of judicial caution

tion of an atheist. See Ercole, Guido Cavalcanti called judicatum solvi, given in cases of general BARTOLOMMEO (1503-62), a noble and eloquent

e le sue Rime (Milan, 1885). —Another of the name, loosing of arrestment of ships, in which the surety Florentine, led à revolt against the Medici, and becomes liable for the whole debt. The commonest form of judicial caution, however, is the security

was afterwards employed by Pope Paul III. usually given in the Bill Chamber (q.v.), when a bill Cavalcaselle, GIOVANNI BATTISTA, Italian or bond is brought under suspension; the security is art writer, born 22d January 1820, at Legnago, for the principal sum and expenses, if the suspen- early visited the art centres of Italy, and in 1846 sion should be refused. Interdict is also frequently proceeded to Germany, where he met J. A. Crowe granted upon caution for the damages that may 19.v.), with whom he returned to Italy. Banished result from the interdict, should it turn out to have for his share in the revolution of 1848, he acconbeen wrongly obtained.

panied Crowe to London, and there their first joint Cauvery. See KAVERI.

work, Early Flemish Painters (1857 ; 3d ed. 1879), Cava del Tirreni, a town of Italy, in a lovely 1858, and in 1861 commenced with Crowe the History

was published. Cavalcaselle returned to Italy in valley, 54 miles NW. of Salerno by rail, with a cathedral, and manufactures of silk, woollens, of Painting in Italy (Lond. 5 vols. 1861-71). Other cotton, and linen. Pop. 6339. 'About'a mile dis joint works are Titian (1876) and Raphael (1883); tant is the Benedictine monastery of the Trinity, importance. He is head of the art department in

Cavalcaselle's independent writings are of less celebrated for its archives.

the ministry of Public Instruction at Rome. Cavagnari, Sir LOUIS, born in France in 1841,

Cavalier (Fr., from Lat. caballus, 'a nag’), was educated at Christ's Hospital, London, and in 1857 was naturalised as a British subject. He had

from 'horseman’acquired the meaning of 'knight' seen twenty-one years' military and political service

or 'gallant, in which sense it is used by Shakein India, when on 3d September 1879 he was

speare (Henry V., III. 24), like cavalero, in Henry murdered at Kabul. See AFGHANISTAN.

IV., Part II., V. ij. 62. In 1641 · Cavaliers' was

applied as a nickname to Charles's partisans in Cavaignac, LOUIS EUGÈNE, born in Paris, 15th opposition to the Roundheads, or friends of the October 1802, was a son of General Jean Baptiste Parliament; and from a term of reproach it came Cavaignac (1762-1829), a member of the National to be adopted as a title of honour, until, after 1679, Convention. Educated for the military profession, it was superseded by "Tory.' For the Cavalier he first served in the Morea, and afterwards in Parliament' (1661–79), see ČHARLES II. Africa, whither he was sent in 1832 into a kind of honourable exile, in consequence of a too free ex

Cavalier, JEAN, a journeyman baker, from

Ribaute, near Anduze, who, born in 1681, in 1702 pression of opinion in favour of republican institutions . Here he won great distinction by his energy,

became a famous leader of the Camisards (4.v.),

He surrendered coolness, and intrepidity, was made chef de bataillon to Villars in 1704, and entered the service of in 1837, and rose to the rank of brigade-general in Savoy ; but in 1711 we find him settled with a 1844. In 1848 he was appointed governor-general British pension in England, and he died at Chelsea, tionary dangers, was called to Paris and assumed governor of Jersey, 17th May 1740. See a long the office of Minister of War. He was appointed article, in vol. ix. of the Dict. of National Bio military dictator in order to suppress the formid-graphy (1887). able insurrection of June, which he quelled only

Cavaliere Servente. See CICISBEO. after a most obstinate contest continued from Cavalry is a general name for horse-soldiers or the 23d to the 26th June. It is estimated that a troopers trained to act in a body. In the British greater number of Frenchmen fell in the struggle army there are 31 regiments of European, and 30 of

The former comprise 2 Cavaignac's clemency to the vanquished was equal l regiments of Life Guards (red), 1 of Horse Guards

[ocr errors]
[ocr errors][merged small][merged small][merged small][merged small]
[ocr errors][ocr errors][merged small]

and 11 wagons.

[ocr errors][merged small]

(blue), and 7 of Dragoon Guards, classified as heavy | in front, and the 'serrefiles,' or supernumerary non-
cavalry; 3 regiments of Dragoons, and 5 of Lancers, commissioned officers, in rear. There is an interval
classified as medium; and 13 Hussar regiments or of 12 yards between squadrons. The pace is, walk
light cavalry—all carrying carbines and swords. 4 miles an hour, trot 8, gallop 12. The maximum
The war strength of each is 1 lieutenant-colonel, distance covered by cavalry is 68 miles by day
1 major, 8 captains, 9 lieutenants, 7 sub-lieutenants (6 A.M. to 10 P.M.) and 18° by night—86 for the
1 adjutant, 1 paymaster, 1 quartermaster, 1 medical | 24 hours; but after such a march there must be a
officer, 1 veterinary surgeon, 75 non-commissioned rest all next day. For a continuous march 35
officers, 8 farriers, 8 shoeing-smiths, 8 trumpeters, miles a day, at 5 miles an hour, is a good rate.
4 saddlers, 2 wheelers, 15 bandsmen, 480 troopers, Duties on Service.-In large armies, from one-
and 22 drivers, 559 riding and 44 draught horses, eighth to one quarter of the whole force should be

cavalry. Their duties are to cover the movements
The native Indian cavalry are all light, and some of their own army, and to find out those of the
have the front ranks armed with lances, the rear enemy—besides taking part in the actual battles by
with sabres. Bengal has 19 regiments, each of 8 guarding the flanks, seizing all opportunities of
troops, consisting of 10 European officers (1 in com- charging, completing success by an active pursuit,
mand and I surgeon), 17 native officers, and 536 or covering defeat. The screening and reconnoitring
native non-commissioned officers and troopers. duties are performed by the cavalry divisions, each
Madras has 4 regiments of only 6 troops each, the of two or more brigades, one or two days' march in
same number of European, but 12 native officers front of the main body. The light Brigades (q.v.)
and 396 of other ranks. Bombay has 7 regiments are perhaps best for the actual scouting, but must
with the same organisation and numbers as Bengal, be supported by heavy cavalry in order to meet that
but only 518 native non-commissioned officers and of the enemy, which would otherwise have the
troopers. Besides these regiments there is a troop advantage of greater weight in the charge. Each
of native cavalry at Aden, and one as a body-guard brigade of two or more regiments is accompanied
for each lieutenant-governor, and the governor- by à battery of Horse Artillery.
general of India.

The battle of Mars la Tour in the Franco-German The auxiliary cavalry in Great Britain comprises war of 1870, supplies the best examples of a cavalry 39 regiments of Yeomanry, 2 of Volunteer Light fight on a large scale, and of a charge (that of Horse, and I of Volunteer Mounted Rifles, of various Barby and Bredows' brigades) directed against instrengths. There is a cavalry depôt at Canterbury, fantry. The action of the German cavalry through. and a school of instruction for auxiliary cavalry at out the same campaign illustrates the screening and Aldershot.

reconnoitring duties of the arm. The capture of After the American civil war, the United Cairo by the rapid advance of the British cavalry States' cavalry was reduced to 10 regiments of after the battle of Tel-el-Kebir (1882), shows its 936 privates each. The commissioned officers of value after a successful engagement. a regiment consist of 1 colonel, 1 lieutenant Tactics.-Unless acting dismounted, cavalry must colonel

, 3 majors, 12 captains, 14 first lieutenants, either attack or retire; it cannot otherwise defend and 12 second lieutenants,

itself. Against cavalry it must therefore manæuvre History.

For the place of cavalry in the ancient with its first line, so as to attack to the best advanarmies, see ARMY. In the middle ages horsemen tage-i.e. against the adversary's flank. Its second -knights, esquires, and their attendants—formed line following, en échelon, in order to have a clear the most important part of the great armies ; but front, protects the flanks of the first from counter after the disappearance of the Roman cohort with attack, and supports its movement, completing its its 132 highly trained horsemen, the organisation victory, or covering its retreat. Horse artillery of cavalry, as we now understand the word, was on the protected flank fire upon the enemy up to the neglected until 1445, when Charles VII. of France last moment before the charge. A third portion, grouped his men-at-arms into companies 100 strong. formed into a reserve, follows, and behind it the The method of fighting, from 1645 until Frederick other two can rally after the charge, which, even the Great introduced the charge or shock tactics, when successful, creates great confusion. Cavalry was to advance to close quarters, fire pistols from attacks artillery in two bodies--one in line formathe saddle, and then commence cutting with the tion charges the escort, and the other in extended sword. The value of dismounted cavalry able to order, the men a horse's length apart, converges act as infantry was then recognised, and dragoons upon the guns. Infantry can defend itself from a armed with muskets were much in vogue until the cavalry charge, unless surprised by a flank attack, beginning of the 19th century. They then lost which would generally be delivered by comparafavour, and though all European nations continued tively small bodies in successive lines, but such an to train their troopers to dismount and use their opportunity rarely occurs on a modern battlefield. carbines to hold some important point until the

Cav'an, an inland county in the south of Ulster. arrival of infantry, it was taught that the sword

It lies in the narrowest part of Ireland, 18 miles was their proper weapon, and the saddle their from the Atlantic, and 20 from the Irish Sea. Area, proper place. But Russia has lately armed all her 746 sq. m., of which less than a third is under crops. cavalry, except the Cossacks, with long rifles, thus Bogs and hills, with many

small lakes, are found in turning them into dragoons, and it is now generally the north-west, where Cuilcagh attains a maximum felt that the dismounted service of cavalry

must be altitude of 2188 feet. The chief rivers are the Erne, developed to a greater extent than has hitherto the Woodford, and the Annalee. The eastern half of been the case. Mounted infantry too, using their Cavan rests on clay-slate and graywacke; the mounhorses merely as a means of rapidly covering the tain district in the west is carboniferous formation, ground, have been found so useful in the British Of minerals, Cavan affords coal, iron, lead, and army, that in 1887 a school for this arm was formed at Aldershot ; and it has been decided that a force cold and damp; and the soil is poor, wet, and

copper, with many mineral springs. The climate is 900 strong shall accompany the cavalry division on

clayey, except along the streams. The chief crops active service.

are oats and potatoes, the

cultivation of flax having Formation.--A cavalry regiment in the field is greatly decreased since 1850. The farms are small divided into 4 squadrons, each of 2 troops. The Agriculture forms the staple industry, but linen is men of each squadron when in line are 6 inches manufactured to a considerable extent. The chief from knee to knee, and formed in two ranks, a horse's

towns are Cavan, Cootehill, and Belturbet. Cavan length apart. The officers are at a similar distance returns two members to parliament. Pop. (1851)

[ocr errors]
[blocks in formation]
[ocr errors][ocr errors][merged small]
[ocr errors]

174,064; (1881) 129,476 ; (1891) 111,679, of whom these are simply great blisters or hollows formed 90,329 were Catholics, and 16,325 Episcopalians.- | by the expansive power of the highly heated CAVAN, the county town, stands on a branch of the vapours contained in the lava at the time of its Annalee, 85 miles NW. of Dublin by rail. It has eruption. Others again may have been caused by acourt-house and a grammar-school ; and the beau the sudden conversion into steam of the water of tiful demesne of Lord Farnham lies between Cavan lakes or streams suddenly overwhelmed by a lava. and Lough Oughter, which is about 5 miles west. flow-the steam thus generated might either Pop. about 3000).

violently rupture the lava by its explosive force, or Cavati'na, a short form of operatic air, of a

produce great tunnels and irregular cavities under smooth and melodious character, differing from the

the liquid lava, already inclosed in its solid crust, ordinary aria in consisting only of one part, and by pressing it upwards. The extensive Fossa

della Palomba of Etna is supposed by some to have frequently appearing as part of a grand scena.

had such an origin. But probably the greater Examples of cavatina are found in many wellknown operas, as Sonnambula and Les Huguenots. formed by the escape of the lava itself from its own

number of the larger caves under lava have been The term is also often used for a complete air or

solidified envelope. When lava pours out from a song, such as the “Salve dimora'in Faust.

volcanic orifice it very rapidly coagulates above Cave, or CAVERN (Lat. cavus, 'hollow'). The and below, so that the liquid rock becomes imnatural hollows which occur in and underneath prisoned in a hardened crust of its own material. rocks have originated in various ways-some being The great pressure of the inclosed lava, however, due to the chemical and mechanical action of upon the crust at the terininal point of the flow water, others to dislocations and disruptions pro- suffices again and again to rupture it, and the lava duced by movements of the crust, or by superficial then flows out freely until it is again imprisoned in rock-falls and landslips, while yet others are tunnels the same manner. In the case of very liquid lavas which now and again occur in or under thick sheets this escape is often completed in a perfect manner of lava. Caves formed by marine erosion are fre —and a long underground tunnel is left behind, quently met with along the coast-line of Britain and from the roof of which depend long stalactites of other countries, Fingal's Cave at Staffa (q.v.) being black glassy lava. Extensive caves formed in this a splendid example. They are not confined to any way-some of them measuring over 100 feet in particular kind of rock—although, other things width-occur in the Azores, the Canary slands, being equal, they are of course more easily formed Iceland, and other volcanic regions. in readily yielding rocks than in more durable kinds. Another class of caves embraces such hollows It is rather the character of their natural division as have originatel during earthquakes or other planes or beds and joints than their composition movements in the crust of the earth. At such and texture that determines whether the rocks at times rocks are rent asunder, and when they fall the base of a sea-cliff shall be hollowed out or not rudely together irregular cavities are left between by the action of the waves. If the rocks are thin the disjointed masses, and similar results often bedded and abundantly and regularly jointed, it is take place when great landslips occur. But the obvious that as soon as any portion is undermined most extensive caves and underground galleries by the sea, the overlying masses will immediately have been excavated by the chemical and mechanyield along their division-planes and topple down. ical action of underground water. Sometimes If, on the other hand, the rocks are meagrely and these hollows continue more or less persistently irregularly jointed, and occur in massive beds, then in one direction, but most usually they wini they will not so readily collapse when undermined, tortuously about, and often open into similar and caves will tend to be formed. Caves which intricate galleries, which, in like manner, comhave had this origin are not uncommonly met with

municate with lateral extensions of the same charalong the line of old sea-margins in many regions | acter. There can be no doubt that caves of this which have been elevated in recent geological | kind are the channels of underground streams and times. Most frequently, however, the entrances rivers, and that they have been excavated, in the to such caves are concealed by the rock-rubbish first place, by the chemical action of acidulated which has been detached from time to time by the water making its way downwards from the surface action of the weather from the cliffs above. along the natural division-planes of the rocks, Caves of erosion are also formed by river-action until eventually space has been licked out for the at the base of crags and cliffs in many valleys. passage of a subterranean stream. The cavities And now and again such hollows may be detected would then tend to be enlarged by the filing action at various levels in river-cliffs, as if they had been of the sand and gravel which the underground formed during the gradual excavation of the ravines stream and its numerous feeders might sweep in which they occur.

along. Many such underground watercourses are In Britain and other countries long occupied by well known at the present day, and the direction man most of such river-cliff caves or rock-shelters of some of them can be traced by the swallow-holes, have been artificially deepened and widened, and chasms, and sinks, which indicate places where this to such an extent that it is often hard to the roofs of the cavities have given way, or have say how much of the work can be attributed to been pierced by the action of acidulated water. In nature. By far the most important caves, how certain regions almost all the drainage is thus conever, are those which owe their origin to the ducted underground-rivers after flowing for a action of underground water. But before these are considerable distance at the surface suddenly disdescribed, mention may be made of the hollows appear, and follow a hidden course, for it may be which occur now and again in and under lava many miles, before they emerge again to the light flows. Where lava has flowed over and solidified of day. Sometimes, indeed, they never come to abore a mass of snow and ice, the subsequent the surface again, but enter the sea by subterranean melting of the latter will leave a hollow behind. channels. Should anything occur (such as earthNear the C'asa Inglese, on the south-east side of the quakes, &c.) to interrupt such a system of underhighest cone of Étna, a mass of ice of unknown ground drainage, and the streams and rivers be extent and thickness, covered by lava, was seen compelled into new channels, the old subterranean by Lyell in 1828 and again in 1858. But this, courses will then become galleries more or less dry, it must be remembered, is at a height of 10,000 | which may be accessible by one or even by several feet above the sea.

In lava itself, however, , openings. caves of considerable extent occur.

Many of

As it cannot be doubted that all such great

[ocr errors][ocr errors]
[blocks in formation]
[ocr errors]


[ocr errors][ocr errors][merged small]

underground galleries owe their inception entirely times many animals may have been entrapped in to the chemical action of water seeking its way the same way-for broken and rubbed bones often downwards from the surface, and following the occur, sometimes very abundantly, in the old torrenlines of natural division-planes in the rocks, it is tial accumulations of deserted subterranean waterobvious that caves will be of most common occur

When the galleries ceased to be traversed rence in regions where the rocks yield most readily by streams, stalagmitic accretions would then begin to such chemical action. Among the more soluble to accumulate over the shingle and debris beds. rocks are rock-salt and gypsum, but these are only In course of time many of these subterranean locally developed in such quantities as to give rise hollows, becoming more or less accessible from the on their removal to underground cavities of any outside, were occupied by carnivorous animals, extent. Calcareous rocks, more especially limestone, who carried thither their prey, and thus by and have not only an almost world-wide distribution, by accumulations of bones were formed, which but they also occur in greater mass than either the drip of water from above gradually inclosed gypsum or rock-salt, and hence, although not so in calcareous matter, and eventually covered readily acted upon by water as the latter two, it is up under a sheet of stalagmite. Now and again in limestones that nearly all the most renowned the caves were occupied for shorter or longer caves and subterranean galleries appear.

periods by man—his presence being still evidenced Many caverns have a calcareous incrustation by his implements and weapons, by charred and lining their interior. Sometimes this deposit is split bones, &c., and occasionally by portions of his pure white; it is, however, more generally coloured own skeleton—and these relics, in like manner, by the impurities which the water, percolating subsequently became sealed up in a more or less downwards from the surface, has taken up from the thick accumulation of stalagmite. Some of these superincumbent rocks. To the incrustations which bone-caves contain the record of many physical are suspended from the roof like icicles, the name changes. Thus, we have evidence to show that stalactites is given, while those rising from the floor after having been the haunt of wild beasts or the are called stalagmites. The origin of these is as abode of man for some indefinite but often profollows: Water which has percolated down from longed period, the cave again gave passage to a flow the surface always contains à certain proportion of of water, and deposits of loam, clay, or gravel, &c. carbonic acid-it is acidulated water—the acid were laid down upon the stalagmitic pavement and being derived from the atmosphere and the decaying bone-breccia. Or, as in some cases, the stalag. organic matter of the soil, &c. Water thus charged mite, together with bones covered by and inclosed with carbonic acid has the power of dissolving within it, was broken up and partially or wholly limestone-i.e. it takes up a certain proportion removed. Then, at a subsequent date the stream of carbonate of lime and converts it into the soluble once more deserted its channel, while carnivores or bicarbonate. Arrived at the roof of a cave it oozes man again returned, and newer heaps of bones and out and is there subject to evaporation, the excess stalagmite accumulated. Commingled with these of carbonic acid is parted with, and a thin pellicle stalagmites of the bone-caves there is almost of carbonate of lime is deposited as an incrustation. always more or less of a reddish earth or clay, When the drops fall to the floor they are subject which is the insoluble residue of the limestone from there in the same way to evaporation, and are thus the dissolution of which the stalactites and stalagcompelled to give up the remainder of the cal- mites are formed. Some of the more remarkable careous matter held in solution. By this constant bone-caves which have yielded testimony as to the dropping and falling, icicle-like pendants grow contemporaneity of man with extinct mammalia, downwards from the roof, while sheets, bosses, and are Kent's Cave (q.v.) and Brixham Cave in Engdomes gradually accumulate upon the floor_until, land, the caves in the valley of the Lesse in Belgium, not infrequently, these stalagmites come at last to the caves of Perigord and the Pyrenees in France, unite with the gradually lengthening stalactites, and the Kesserloch near Thäingen in Switzerland. and so to form, as it were, pillars which look as if Bone-caves containing the remains of post-tertiary they had been placed to support the roof. See the mammals are rare in North America; those of Brazil articles on ADELSBERG, AGTELEK, KENT'S CAVE, have many bones of large rodents and edentates. MAMMOTH CAVE, &c.

For caves at Wick, in Scotland, still occupied by BONE-CAVES. -Caves are of interest to geologists tinkers, see Sir Arthur Mitchell, The Past in the not only because they testify to the potency of the Present (1880). For accounts of special caves, see chemical and mechanical action of underground the British Association Reports (for Kent's Cave) water, but on account of the remarkable evidence and the Philosophical Transactions (1822–73). they have yielded as to the contemporaneity of man For general descriptions, see Buckland's Reliquiæ with many extinct and no longer indigenous mam Diluviance, Dupont's L'Homme pendant les Ages mals. This evidence is furnished by the accum de la Pierre, Lartet's and Christy's Reliquiæ Aqui, ulations which so frequently cover the floors of tanice, Lubbock's Prehistoric Times, Dawkins' caverns to a greater or less depth. The accumula-Cave-hunting, J. Geikie's Prehistoric Europe. For tions in question consist partly of clay, sand, gravel, further information as to the European caveand shingle, and partly of red earth and sheets of dwellers of prehistoric times, see MAN, FLINT stalagmite. Some of these are doubtless the | IMPLEMENTS, PLEISTOCENE. alluvial detritus carried forward by underground ARTIFICIAL CAVES. –The primitive inhabitants streams. This detritus often consists largely of of most civilised countries and many primitive angular, subangular, and water-worn fragments of tribes at the present day have been troglodytes or limestone, which have doubtless been derived from cave-dwellers. In many countries where natural the roof and walls of the rground galleries, caves are either of rare occurrence or do not occur but not infrequently, the presence of other kinds at all, certain rock-exposures have been artifici. of rock-fragments shows that no inconsiderable ally excavated, and occupied either permanently amount of material has been introduced from the as dwelling-places or occasionally as retreats in outside by the streams as they plunged into their times of danger, while others have been used as subterranean courses. Much debris also may have cells, hermitages, or burial-places. Such caves are been swept in by heavy rain or flooded torrents not uncommon in the cliffs of Scottish river ravines, washing down through the sinks and swallow-holes as at Hawthornden near Edinburgh, and in the that so frequently pierce the roofs of subterranean valley of the Jed, Roxburghshire. Čaves of this watercourses. These sinks often become pitfalls to kind°eccur usually in rocks that are readily dug unfortunate cattle in our own day, and in former | into, such 'as soft sandstone. Now and again,

[ocr errors]
« PrécédentContinuer »