Chapter IX: Part 9

Electrically driven timepieces may be divided under two heads:--(a) those in which the electric current drives either the pendulum or some lever which operates upon it, which lever or pendulum in turn drives the clock hands; and (b) those timepieces which are driven by a weight or spring which is periodically wound up by electricity--in fact electrical remontoires.

The simplest clock of the first character that could be imagined would be constructed by fastening an electromagnet with a soft iron core to the bottom of a pendulum, and causing it to be attracted as the pendulum swings by another electromagnet fixed vertically under it (fig. 29). As the pendulum approached the vertical and was say half an inch from its lowest point, the current would be switched on, and switched off as soon as the pendulum got to its lowest point. A very small attraction with this arrangement, probably about a grain weight, acting through the 1/2 in. would drive a heavy pendulum. A switch would have to be worked in connexion with the pendulum. A strip of ebonite with a small face of metal on the end of one side, such as a b (fig. 29) might be pivoted at one end on the pendulum with a weak spring to keep it where free along the rod. As the pendulum swung by this would be swept on its journey from left to right against a fixed pin P. This would complete the electric circuit down through the pendulum rod, round the coil on the bottom of the pendulum, through the switch into the pin P, thence through the fixed electromagnet, and so back to the battery. On the return journey no contact would be made because only the ebonite face of the switch would touch P. The pendulum would thus receive an impulse every other vibration. We have described this switch, not to advocate it, but to warn against its use. For the contact would be quite insufficient. In order that the switch might not unduly retard the pendulum it must be light, but this would make the pressure on P too light to be trustworthy. Moreover, the strength of the impulse would vary with the strength of the battery, and hence the arc would be repeatedly uneven.

In contrast with this, let us consider a clock that is now giving excellent results at the Observatory of Neuchatel in Switzerland on Hipp's system (_La Pendule electrique de precision_, Neuchatel, 1884 and 1891). The pendulum (fig. 30) consists of two rods of steel joined by four bridges, one just below the suspension spring, the next about 12 in. lower, the next about half way down, and the last supporting a glass vessel of mercury which forms the bob. On the third of them is placed an iron armature, which works between the poles of an electromagnet fixed to the case, and by which the pendulum is actuated. The circuit is closed and broken by a flipper, which is swayed to and fro by a block fixed to the pendulum at the second bridge. As long as the flipper is merely swayed, no contact takes place, but when the arc of vibration of the pendulum is diminished the flipper does not clear the block but is caught by a nick in it, and forced downwards. In this way the circuit is closed. Fig. 31 is a diagram of the apparatus. When the block g attached to the pendulum catches and presses down the flipper s, the lever l l is rocked over, so that a contact is made at k, and the current which enters the lever l through the knife edge m, runs through the second lever n n, down through the knife edge o, to the battery, and through the electromagnet b which causes the armature a to be attracted. As the block g goes on and releases s, the lever l again falls upon the rest p, the lever n follows it a part of the way till it is stopped by the contact q; this shortcircuits the electromagnet and prevents to a large extent the formation of an induced current. It is claimed that sparking is by this method almost entirely avoided. It is only when s is caught in the notch of the block g that s is pressed down, so that the electric attraction only takes place every few vibrations. This ingenious arrangement makes the working of the clock nearly independent of the strength of the battery, for if the battery is strong the impulses are fewer and the _average arc_ remains the same. The clock is enclosed in an airtight glass case so as to avoid barometric error. It was tested in 1905 at the Neuchatel observatory. In winter in a room of a mean temperature of 35 deg. F. it was 1/4 sec. too slow, in summer when the temperature was 70 deg., it was 1/2 sec. too fast. In the succeeding winter it became .53 sec. too slow again, thus gaining a little in summer and losing in winter. Its average variation from its daily rate was, however, only .033 sec.

In another system originated by G. Froment, a small weight is raised by electricity and allowed to fall upon an arm sticking out at right angles to the pendulum in the plane of its motion, so as to urge it onwards. The weight is only allowed to rest on the arm during the downward swing of the pendulum. The method is not theoretically good, as the impulse is given at the end of the vibration of the pendulum instead of at its middle position.

In the clock invented by C. Fery (chef des travaux pratiques at the Ecole de Physique et Chimie, Paris), an electric impulse is given at every vibration, not by a battery but by means of the uniform movement of an armature which is alternately pulled away from and pushed towards a permanent horseshoe magnet. Currents are thus induced in a bobbin of fine wire placed between the poles of the horseshoe magnet. The movements of the armature are produced by another horseshoe magnet actuated by the primary current from a battery which is turned on and off by the swinging of the pendulum. The energy of the induced current that drives the clock depends solely on the total movement of the armature, and is independent of whether that movement be executed slowly or rapidly, and therefore of the strength of the battery.

_Electrical remontoires_ possess great advantages if they can be made to operate with certainty. For they can be made to wind up a scape-wheel just as is done in the case of the arrangement shown in fig. 16 so as to constitute a spring remontoire, or better still they can be made to raise a weight as in the case of the gravity train remontoire (fig. 15) but without the complications of wheel-work shown in that contrivance. Of this type one of the best known is that of H. Chesters Pond. A mainspring fixed on the arbor of the hour wheel is wound up every hour by means of another toothed wheel riding loose on the same arbor and driven by a small dynamo, to which the other end of the mainspring is attached. As soon as the hour wheel has made one revolution (driven round by the spring), a contact switch is closed whereupon the dynamo winds up the spring again exactly as the train and fly wind up the spring in fig. 15. These clocks require a good deal of power, and not being always trustworthy seem to have gone out of use. A contrivance of this kind now in use is that patented by F. Hope Jones and G.B. Bowell, and is represented in fig. 32. A pendulum is driven by the scape-wheel A, and pallets B B in the usual way. The scape-wheel is driven by another wheel C which, in turn, is driven by the weighted lever D supported by click E engaging the ratchet wheel F. This lever is centred at G and has an extension H at right angles to it. J is an armature of soft iron pivoted at K and worked by the electromagnet M. D gradually falls in the act of driving the clock by turning the wheels C and A until the contact plate on the arm H meets with the contact screw L at the end of the armature J, thus completing the electrical circuit from terminal T to terminal T' through the electromagnet M, and through any number of step-by-step dial movements which may be included in the same series circuit. The armature is then drawn towards the magnet with rapid acceleration, carrying the lever D with it. The armature is suddenly arrested by the poles of the magnet, but the momentum of the lever D carries it farther, and the click E engages another tooth of the ratchet F. A quick break of the circuit is thus secured, and the contact at L is a good one, first because the whole of the energy required to keep the clock going, or in other words the energy required to raise the lever D is mechanically transmitted through its surfaces at each operation, and secondly, owing to the arrangement of the fulcrums at G and K which secure a rubbing contact. The duration of the contact is just that necessary to accomplish the work which has to be done, and it is remarkable that when used to operate large circuits of electrically propelled dials the duration accommodates itself to their exact requirements and the varying conditions of battery and self-induction. The ratchet wheel F is usually mounted loosely upon its arbor and is connected to the wheel C by means of a spiral spring, which in conjunction with the back-stop click P maintains the turning force on the wheelwork at the instant when the lever D is being raised.

Electrically driven dials usually consist of a ratchet wheel driven by an electrically moved pall. Care has to be taken that the pushes of the pall do not cause the ratchet wheel to be impelled too far. The anchor escapement of a common grandfather's clock can be made to drive the works by means of an electromagnet, the pendulum being removed. With a common anchor escapement the scape-wheel can be driven round by wagging the anchor to and fro. All then that is necessary is to fix a piece of iron on the anchor so that its weight pulls the anchor over one way, while an electromagnet pulls the iron the other. Impulses sent through the electromagnet will then drive the clock. If the clock is wound up in the ordinary way the motion will be so much helped that the electric current has very little to do, and thus may be very feeble. Fig. 33 shows the dial-driving device of Hope Jones's clock. Each time that a current is sent by the master-clock, the electromagnet B attracts the pivoted armature C, and when the current ceases the lever D with the projecting arm E is driven back to its old position by the spring F, thus driving the wheel A forward one division. G is a back-stop click, and H, I, fixed stops.

It seems doubtful whether in large towns a number of dials could be electrically driven from a distance because of the large amount of power that would have to be transmitted. But for large buildings, such as hotels, they are excellent. One master-clock in the cellar will drive a hundred or so placed over the building. The master-clock may itself be driven by electricity, but it will require the services from time to time of some one to correct the time. Even this labour may be avoided if the master-clock is _synchronized_, and as synchronization requires but a small expenditure of force, it can be done over large areas. Hence the future of the clock seems to be a series of master-clocks, electrically driven, and synchronized one with another, in various parts of a city, from each of which a number of dials in the vicinity are driven. Electrical synchronization was worked out by Louis Breguet and others, and a successful system was perfected in England by J.A. Lund. The leading principle of the best systems is at each hour to cause a pair of fingers or some equivalent device to close upon the minute hand and put it exactly to the hour. Other systems are designed to retard or to accelerate the pendulum, but the former appears the more practical method. There is probably a future before synchronization which will enable the services of a clockmaker to be largely dispensed with and relegate his work merely to keeping the instruments in repair.

_Miscellaneous Clocks._--Some small clocks are made to go for a year. They have a heavy balance wheel of brass weighing about 2 1b and about 2-1/2 in. in diameter, suspended from a point above its centre by a fine watch spring about 4 in. long. The crutch engages with the upper part of the spring, and as the balance wheel swings the pallets are actuated. The whole clock is but a large watch with a suspended balance wheel, oscillating once in about 8 seconds. Unless the suspension spring be compensated for temperature, such clocks gain very much in winter.

An ingenious method of driving a clock by water has been proposed. As the pendulum oscillates to one side, an arm on it rises and at last lightly touches a drop of water hanging from a very fine nozzle; this drop is taken off and carried away by the arm, to be subsequently removed by adhesion to an escape funnel placed below the arm. Hence at each double vibration of the pendulum part of the work done by a drop of water falling through a short distance is communicated to the pendulum, which is thus kept in motion as long as the water lasts. At this rate a gallon of water ought to drive the clock for 40 hours. Care of course must be taken to keep the water in the reservoir at a constant level, so that the drops formed shall be uniform.

If it were worth while, no doubt the oscillations of a pendulum working in a vacuum could be maintained by the communication and discharge at each oscillation of a slight charge of electricity; or again, heat might at each oscillation be communicated to a thermo-electric junction, and the resulting current used to drive the pendulum.

The expansions and contractions of metal rods under the influence of the changes of temperature which take place in the course of each night and day have also been employed to keep a clock wound up, and if there were any need for it no doubt a small windmill rotating at the top of a tower would easily keep a turret clock fully wound, by a simple arrangement which would gear the going barrel of the clock to the wind vane motion, whenever the weight had fallen too low, and release it when the winding up was completed. Even a smoke jack would do the same office for a kitchen clock.

The methods of driving astronomical telescopes by means of clockwork will be found in the article TELESCOPE. Measurements of small intervals of time are performed by means of chronographs which in principle depend on the use of isochronous vibrating tuning-forks in place of pendulums. In practice it is needful in most cases that an observer should intervene in time measurements, although perhaps by means of a revolving photographic film a transit of the sun might be timed with extraordinary accuracy. But if the transit of a star across a wire is to be observed, there is no mode at present in use of doing so except by the use of the human eye, brain and hand. Hence in all such observations there is an element of personal error. Unfortunately we cannot apply a microscope to time as we can to space and make the cycle of events that takes place in a second last say for five minutes so as to time them truly. By personal observations the divisions of a second cannot in general be made more accurately than to 1/10 or 1/15 of a second. The most rapid music player does not strike a note more than 10 or 12 times in a second. It is only in case of recurring phenomena that we can make personal observations more accurate than this by taking the mean of a large number of observations, and allowing for personal error. For the purpose of determining longitude at sea accuracy to 1/30 of a second of time would find the place to about 20 yards. It seems to follow that the extent to which astronomical clocks can be made accurate, viz. to 1/30 of a second average variation from their mean daily rate, or one two-and-a-half millionth of 24 hours, is a degree of accuracy sufficient for present purposes, and it seems rather doubtful whether mechanical science will in the case of clocks be likely to reach a much higher figure.

In the 17th century it was a favourite device to make a clock show sidereal time as well as mean solar time. The length of the sidereal day is to the mean solar day as .99727 to 1, and various attempts have been made by trains of wheels to obtain this relation--but all are somewhat complicated.

_Magical clocks_ are of several kinds. One that was in vogue about 1880 had a bronze figure on the top with outstretched arm holding in its hand the upper part of the spring of a pendulum, about 10 in. long. The pendulum had apparently no escapement and the puzzle was how it was maintained in motion. It was impossible to detect the mystery by the aid of the eye alone; the truth, however, was that the whole figure swung to and fro at each oscillation of the pendulum, to an amount of 1/400 of an inch on the outside rim of the base. A movement of 1/400 of an inch per half second of time is imperceptible; it would be equivalent to perception of motion of the minute hand of a clock about 6 in. in diameter, which is almost impossible. The connexion of the figure to the anchor of the escapement was very complicated, but clocks of the kind kept fair time. A straw, poised near the end on a needle and with the short end united by a thread to the bronze figure, makes the motion apparent at once and discloses the trick. Another magical clock consists of two disks of thin sheet glass mounted one close behind the other, one carrying the minute hand and the other the hour hand. The disks rest on rollers which rotate and turn them round. The front and back of the movable disks are covered by other disks of glass surrounded by a frame, so that the whole looks simply like a single sheet of glass mounted in a frame, in the centre of which the hands rotate, without any visible connexion with the works of the clock.

Clocks have been made with a sort of balance wheel consisting of a thread with a ball at the end which winds backwards and forwards spirally round a rod. In others a swing or see-saw is attached to the pendulum, or a ship under canvas is made to oscillate in a heavy sea. In others the time is measured by the fall of a ball down an inclined plane, the time of fall being given by the formula t = sqrt(2s/(g sin a)), where s is the length of the incline and a the inclination. But friction so modifies the result as to render experiment the only mode of adjusting such a clock. Sometimes a clock is made to serve as its own weight, as for instance when a clock shaped like a monkey is allowed to slide down a rope wound round the going barrel. Or the clock is made of a cylindrical shape outside and provided with a weighted arm instead of a going barrel; on being put upon an incline, it rolls down, and the fall supplies the motive power.

Clocks are frequently provided with chimes moved exactly like musical boxes, except that the pins in the barrel, instead of flipping musical combs, raise hammers which fall upon bells. The driving barrel is let off at suitable intervals. The cuckoo clock is a pretty piece of mechanism. By the push of a wire given to the body of the bird, it is bent forward, the wings and tail are raised and the beak opened. At the same time two weighted bellows measuring about 1 X 2 in. are raised and successively let drop. These are attached to small wooden organ pipes, one tuned a fifth above the other, which produce the notes. Phonographs are also attached to clocks, by which the hours are called instead of rung.

Clocks are also constructed with conical pendulums. It is a property of the conical pendulum that if swung round, the time of one complete revolution is the same as that of the double vibration of a pendulum equal in length to the vertical distance of the bob of the conical pendulum below its point of support. It follows that if the driving force of such a pendulum can be kept constant (as it easily can by an electric contact which is made at every revolution during which it falls below a certain point) the clock will keep time; or friction can be introduced so as to reduce the speed whenever the pendulum flies round too fast and hence the bob rises. Or again by suitable arrangements the bob may be made to move in certain curves so as to be isochronous. Plans of this kind are employed rather to drive telescopes, phonographs and other machines requiring uniform and steady movement.

Comical and performing clocks were very popular in the 15th and 16th centuries. One at Basel in Switzerland was arranged so as gradually to protrude a long tongue as the pendulum vibrated. It is still to be seen there in the museum. The famous clock at Strassburg, originally constructed in 1574, remade in 1842, displays a whole series of scenes, including processions of the apostles and other persons, and a cock that crows. A fine clock at Venice has two rather stiff bronze giants that strike the hours.

Clocks with complicated movements representing the positions of the heavenly bodies and the days of the week and month, allowance being made for leap year, were once the delight of the curious. Repeating clocks, which sounded the hours when a string was pulled, were once popular. The string simply raised the lifting piece and let the clock strike as the hands would do when they came to the hour. This was of use in the old days when the only mode of striking a light at night was with a flint and steel, but lucifer matches and the electric light have rendered these clocks obsolete.

_Testing Clocks._--The average amount by which a clock gains or loses is called its mean or average daily rate. A large daily rate of error is no proof that a clock is a bad one, for it might be completely removed by pendulum adjustment. What is required is that the daily rate shall be uniform, that is, that the clock shall not be gaining (or losing) more on one day than on another, or at one period of the same day than at another. In fig. 34 A B is a curve in which the abscissae represent intervals of time, the ordinates the number of seconds at any time by which the clock is wrong. The curve C D is one in which the ordinates are proportional to the tangents of the angles of inclination of the curve A B to the axis of x, that is dy/dx. Whenever the line A B is horizontal, C D cuts the axis of x. In a clock having no variation in its daily rate the curve A B would become a straight line, though it might be inclined to the axis of x, and C D, also a straight line, would be parallel to the axis of x, though it might not coincide with it. In a clock set to exact time and having no variations of daily rate, both the curves would be straight lines and would coincide with the axis of x. The curve C D, known as the curve of variation of daily rate, will generally be found to follow changes of day and night, and of temperature, and the fluctuations of the barometer and hygrometer; it is the curve which reveals the true character of the clock. Hence in testing a clock two things have to be determined: first, the daily rate of error, and second, the average variations from that daily rate, in other words the _irregularities_ of going. To test a clock well six months' or a year's trial is needed, and it is desirable to have it subjected to considerable changes of temperature.

The bibliography of horology is very extensive. Among modern works
Lord Grimthorpe's _Rudimentary Treatise on Clocks_, _Watches and
Bells_ (8th edition, London, 1903) is perhaps the most convenient.
Many references to older literature will be found in Thomas Reid's
Treatise on Clock and Watchmaking (1849). (G.; H. H. C.)

_Decorative Aspects._--In art the clock occupies a position of considerable distinction, and antique examples are prized and collected as much for the decorative qualities of their cases as for the excellence of their time-keeping. French and English cabinet-makers have especially excelled, although in entirely different ways, in the making of clock cases. The one aimed at comely utility, often made actually beautiful by fit proportion and the employment of finely grained woods; the other sought a bold and dazzling splendour in which ornament overlay material. It was not in either country until the latter part of the 17th century that the cabinet-maker's opportunity came. The bracket or chamber clock gave comparatively little scope to the worker in wood--in its earlier period, indeed, it was almost invariably encased in brass or other metal; and it was not until the introduction of the long pendulum swinging in a small space that it became customary to encase clocks in decorative woodwork. The long or "grandfather" clock dates from about the fourth quarter of the 17th century--what is, perhaps, the earliest surviving English dated specimen is inscribed with the date 1681. Originally it was a development of the dome-shaped bracket clock, and in the older examples the characteristic dome or canopy is preserved. The first time-keepers of this type had oaken cases--indeed oak was never entirely abandoned; but when walnut began to come into favour a few years later that beautifully marked wood was almost invariably used for the choicest and most costly specimens. Thus in 1698 the dean and chapter of St Paul's cathedral paid the then very substantial price of L14 for an inlaid walnut long-cased eight-day clock to stand in one of the vestries. The rapidity with which the new style came into use is suggested by the fact that while very few long clocks can be certainly dated before 1690, between that year and the end of the century there are many examples. Throughout the 18th century they were made in myriads all over England, and since they were a prized possession it is not surprising that innumerable examples have survived. Vary as they may in height and girth, in wood and dial, they are all essentially alike. In their earlier years their faces were usually of brass engraved with cherubs' heads or conventional designs, but eventually the less rich white face grew common. There are two varieties--the eight-day and the thirty-hour. The latter is but little esteemed, notwithstanding that it is often as decorative as the more expensive clock. The favourite walnut case of the late 17th and early 18th century gave place in the course of a generation to mahogany, which retained its primacy until the introduction of cheaper clocks brought about the supersession of the long-cased variety. Many of these cases were made in lacquer when that material was in vogue; satinwood and other costly foreign timbers were also used for bandings and inlay. The most elegant of the "grandfather" cases are, however, the narrow-waisted forms of the William and Mary period in walnut inlay, the head framed in twisted pilasters. Long clocks of the old type are still made in small numbers and at high prices; they usually contain chimes. During the later period of their popularity the heads of long clocks were often filled in with painted disks representing the moon, by which its course could be followed. Such conceits as ships moving on waves or time with wings were also in favour. The northern parts of France likewise produced tall clocks, usually in oaken cases; those with Louis Quinze shaped panels are often very decorative. French love of applied ornament was, however, generally inimical to the rather uncompromising squareness of the English case, and the great Louis Quinze and Louis Seize cabinetmakers made some magnificent and monumental clocks, many of which were "long" only as regards the case, the pendulum being comparatively short, while sometimes the case acted merely as a pedestal for a bracket-clock fixed on the top. These pieces were usually mounted very elaborately in gilt bronze, cast and chased, and French bracket and chamber clocks were usually of gilded metal or marble, or a combination of the two; this essentially late 18th-century type still persists. English bracket clocks contemporary with them were most frequently of simple square or arched form in mahogany. The "grandfather" case was also made in the Low Countries, of generous height, very swelling and bulbous.

See F. J. Britten, _Old Clocks and Watches and their Makers_ (2nd
edition, London, 1904); Mathieu Planchon, _L'Horloge, son histoire
retrospective, pittoresque et artistique_ (Paris, 1899). (J. P.-B.)

CLODIA, VIA, an ancient high-road of Italy. Its course, for the first 11 m., was the same as that of the Via Cassia; it then diverged to the N.N.W. and ran on the W. side of the Lacus Sabatinus, past Forum Clodii and Blera. At Forum Cassii it may have rejoined the Via Cassia, and it seems to have taken the same line as the latter as far as Florentia (Florence). But beyond Florentia, between Luca (Lucca) and Luna, we find another Forum Clodii, and the Antonine Itinerary gives the route from Luca to Rome as being by the Via Clodia--wrongly as regards the portion from Florentia southwards, but perhaps rightly as regards that from Luca to Florentia. In that case the Clodius whose name the road bears, possibly C. Clodius Vestalis (c. 43 B.C.), was responsible for the construction of the first portion and of that from Florentia to Luca (and Luna), and the founder of the two Fora Clodii. The name seems, in imperial times, to have to some extent driven out that of the Cassia, and both roads were administered, with other minor roads, by the same _curator_.

See Ch. Hulsen in Pauly-Wissowa, _Realencyclopadie_, iv. 63; cf.
CASSIA, VIA. (T. As.)

CLODIUS,[1] PUBLIUS (c. 93-52 B.C.), surnamed PULCHER, Roman politician. He took part in the third Mithradatic war under his brother-in-law Lucius Licinius Lucullus, but considering himself treated with insufficient respect, he stirred up a revolt; another brother-in-law, Q. Marcius Rex, governor of Cilicia, gave him the command of his fleet, but he was captured by pirates. On his release he repaired to Syria, where he nearly lost his life during a mutiny instigated by himself. Returning to Rome in 65, he prosecuted Catiline for extortion, but was bribed by him to procure acquittal. There seems no reason to believe that Clodius was implicated in the Catilinarian conspiracy; indeed, according to Plutarch (_Cicero_, 29), he rendered Cicero every assistance and acted as one of his body-guard. The affair of the mysteries of the Bona Dea, however, caused a breach between Clodius and Cicero in December 62. Clodius, dressed as a woman (men were not admitted to the mysteries), entered the house of Caesar, where the mysteries were being celebrated, in order to carry on an intrigue with Caesar's wife. He was detected and brought to trial, but escaped condemnation by bribing the jury. Cicero's violent attacks on this occasion inspired Clodius with the desire for revenge. On his return from Sicily (where he had been quaestor in 61) he renounced his patrician rank, and, having with the connivance of Caesar been adopted by a certain P. Fonteius, was elected tribune of the people (10th of December 59). His first act was to bring forward certain laws calculated to secure him the popular favour. Corn, instead of being sold at a low rate, was to be distributed gratuitously once a month; the right of taking the omens on a fixed day and (if they were declared unfavourable) of preventing the assembly of the comitia, possessed by every magistrate by the terms of the Lex Aelia Fufia, was abolished; the old clubs or gilds of workmen were re-established; the censors were forbidden to exclude any citizen from the senate or inflict any punishment upon him unless he had been publicly accused and condemned. He then contrived to get rid of Cicero (q.v.) and the younger Cato (q.v.), who was sent to Cyprus as praetor to take possession of the island and the royal treasures. Cicero's property was confiscated by order of Clodius, his house on the Palatine burned down, and its site put up to auction. It was purchased by Clodius himself, who, not wishing to appear in the matter, put up some one to bid for him. After the departure of Caesar for Gaul, Clodius became practically master of Rome with the aid of armed ruffians and a system of secret societies. In 57 one of the tribunes proposed the recall of Cicero, and Clodius resorted to force to prevent the passing of the decree, but was foiled by Titus Annius Milo (q.v.), who brought up an armed band sufficiently strong to hold him in check. Clodius subsequently attacked the workmen who were rebuilding Cicero's house at the public cost, assaulted Cicero himself in the street, and set fire to the house of Q. Cicero. In 56, when curule aedile, he impeached Milo for public violence (_de vi_), when defending his house against the attacks of Clodius, and also charged him with keeping armed bands in his service. Judicial proceedings were hindered by outbreaks of disturbance, and the matter was finally dropped. In 53, when Milo was a candidate for the consulship, and Clodius for the praetorship, the rivals collected armed bands and fights took place in the streets of Rome, and on the 20th of January 52 Clodius was slain near Bovillae.

His sister, CLODIA, wife of Q. Caecilius Metellus Celer, was notorious for her numerous love affairs. It is now generally admitted that she was the Lesbia of Catullus (Teuffel-Schwabe, _Hist. of Roman Lit._, Eng. tr., 214, 3). For her intrigue with M. Caelius Rufus, whom she afterwards pursued with unrelenting hatred and accused of attempting to poison her, see Cicero, _Pro Caelio_, where she is represented as a woman of abandoned character.

AUTHORITIES.--Cicero, _Letters_ (ed. Tyrrell and Purser), _Pro Caelio,
pro Sestio, pro Milone, pro Domo sua, de Haruspicum Responsis, in
Pisonem_; Plutarch, _Lucullus, Pompey, Cicero, Caesar_; Dio Cassius
xxxvi. 16, 19, xxxvii. 45, 46, 51, xxxviii. 12-14, xxxix. 6, 11, xl.
48. See also I. Gentile, _Clodio e Cicerone_ (Milan, 1876); E. S.
Beesley, "Cicero and Clodius," in _Fortnightly Review_, v.; G.
Lacour-Gayet, _De P. Clodio Pulchro_ (Paris, 1888), and in _Revue
historique_ (Sept. 1889); H. White, _Cicero, Clodius and Milo_ (New
York, 1900); G. Boissier, _Cicero and his Friends_ (Eng. trans.,
1897).

FOOTNOTE:

[1] It is suggested (W. M. Lindsay, _The Latin Language_, p. 41) that
he changed his name Claudius into the plebeian form Clodius, in order
to gain the favour of the mob.

CLOGHER, a market village of Co. Tyrone, Ireland, in the south parliamentary division, on the Clogher Valley light railway. Pop. (1901) 225. It gives name to dioceses of the Church of Ireland and the Roman Catholic Church, but the seat of the Roman Catholic bishop is at Monaghan, with the cathedral. The Protestant cathedral, dedicated to St Macartin, dates from the 18th and early 19th century, but St Macartin (c. 500) was a disciple of St Patrick, and it is said that St Patrick himself founded a bishopric here. The name is derived from the Irish _cloch_, a pillar stone, such as were worshipped and regarded as oracles in many parts of pagan Ireland; the stone was preserved as late as the 15th century in the cathedral, and identity is even now claimed for a stone which lies near the church.

CLOISTER (Lat. _claustrum_; Fr. _cloitre_; Ital. _chiostro_; Span. _claustro_; Ger. _Kloster_). The word "cloister," though now restricted to the four-sided enclosure, surrounded with covered ambulatories, usually attached to coventual and cathedral churches, and sometimes to colleges, or by a still further limitation to the ambulatories themselves, originally signified the entire monastery. In this sense it is of frequent occurrence in earlier English literature (e.g. Shakespeare, _Meas. for Meas._ i. 3, "This day my sister should the _cloister_ enter"), and is still employed in poetry. The Latin _claustrum_, as its derivation implies, primarily denoted no more than the enclosing wall of a religious house, and then came to be used for the whole building enclosed within the wall. To this sense the German "Kloster" is still limited, the covered walks, or cloister in the modern sense, being called "Klostergang," or "Kreuzgang." In French the word _cloitre_ retains the double sense.

In the special sense now most common, the word "cloister" denotes the quadrilateral area in a monastery or college of canons, round which the principal buildings are ranged, and which is usually provided with a covered way or ambulatory running all round, and affording a means of communication between the various centres of the ecclesiastical life, without exposure to the weather. According to the Benedictine arrangement, which from its suitability to the requirements of monastic life was generally adopted in the West, one side of the cloister was formed by the church, the refectory occupying the side opposite to it, that the worshippers might have the least annoyance from the noise or smell of the repasts. On the eastern side the chapter-house was placed, with other apartments belonging to the common life of the brethren adjacent to it, and, as a common rule, the dormitory occupied the whole of the upper story. On the opposite or western side were generally the cellarer's lodgings, with the cellars and store-houses, in which the provisions necessary for the sustenance of the confraternity were housed. In Cistercian monasteries the western side was usually occupied by the "domus conversorum," or lodgings of the lay-brethren, with their day-rooms and workshops below, and dormitory above. The cloister, with its surrounding buildings, generally stood on the south side of the church, to secure as much sunshine as possible. A very early example of this disposition is seen in the plan of the monastery of St Gall (see ABBEY, fig. 3). Local requirements, in some instances, caused the cloister to be placed to the north of the church. This is the case in the English cathedrals, formerly Benedictine abbeys, of Canterbury, Gloucester and Chester, as well as in that of Lincoln. Other examples of the northward situation are at Tintern, Buildwas and Sherborne. Although the covered ambulatories are absolutely essential to the completeness of a monastic cloister, a chief object of which was to enable the inmates to pass from one part of the monastery to another without inconvenience from rain, wind, or sun, it appears that they were sometimes wanting. The cloister at St Albans seems to have been deficient in ambulatories till the abbacy of Robert of Gorham, 1151-1166, when the eastern walk was erected. This, as was often the case with the earliest ambulatories, was of wood covered with a sloping roof or "penthouse." We learn from Osbern's account of the conflagration of the monastery of Christ Church, Canterbury, 1067, that a cloister with covered ways existed at that time, affording communication between the church, the dormitory and the refectory. We learn from an early drawing of the monastery of Canterbury that this cloister was formed by an arcade of Norman arches supported on shafts, and covered by a shed roof. A fragment of an arcaded cloister of this pattern is still found on the eastern side of the infirmary-cloister of the same foundation. This earlier form of cloister has been generally superseded in England by a range of windows, usually unglazed, but sometimes, as at Gloucester, provided with glass, lighting a vaulted ambulatory, of which the cloisters of Westminster Abbey, Salisbury and Norwich are typical examples. The older design was preserved in the South, where "the cloister is never a window, or anything in the least approaching to it in design, but a range of small elegant pillars, sometimes single, sometimes coupled, and supporting arches of a light and elegant design, all the features being of a character suited to the place where they are used, and to that only" (Fergusson, _Hist. of Arch._ i. p. 610). As examples of this description of cloister, we may refer to the exquisite cloisters of St John Lateran, and St Paul's without the walls, at Rome, where the coupled shafts and arches are richly ornamented with ribbons of mosaic, and those of the convent of St Scholastica at Subiaco, all of the 13th century, and to the beautiful cloisters at Arles, in southern France; those of Aix, Fontfroide, Elne, &c., are of the same type; as also the Romanesque cloisters at Zurich, where the design suffers from the deep abacus having only a single slender shaft to support it, and at Laach, where the quadrangle occupies the place of the "atrium" of the early basilicas at the west end, as at St Clement's at Rome, and St Ambrose at Milan. Spain also presents some magnificent cloisters of both types, of which that of the royal convent of Huelgas, near Burgos, of the arcaded form, is, according to Fergusson, "unrivalled for beauty both of detail and design, and is perhaps unsurpassed by anything in its age and style in any part of Europe." Few cloisters are more beautiful than those of Monreale and Cefalu in Sicily, where the arrangement is the same, of slender columns in pairs with capitals of elaborate foliage supporting pointed arches of great elegance of form.

All other cloisters are surpassed in dimensions and in sumptuousness of decoration by the "Campo Santo" at Pisa. This magnificent cloister consists of four ambulatories as wide and lofty as the nave of a church, erected in 1278 by Giovanni Pisano round a cemetery composed of soil brought from Palestine by Archbishop Lanfranchi in the middle of the 12th century. The window-openings are semicircular, filled with elaborate tracery in the latter half of the 15th century. The inner walls are covered with frescoes invaluable in the history of art by Orcagna, Simone Memmi, Buffalmacco, Benozzo Gozzoli, and other early painters of the Florentine school. The ambulatories now serve as a museum of sculpture. The internal dimensions are 415 ft. 6. in. in length, 137 ft. 10 in. in breadth, while each ambulatory is 34 ft. 6. in. wide by 46 ft. high.

The cloister of a religious house was the scene of a large part of the life of the inmates of a monastery. It was the place of education for the younger members, and of study for the elders. A canon of the Roman council held under Eugenius II., in 826, enjoins the erection of a cloister as an essential portion of an ecclesiastical establishment for the better discipline and instruction of the clerks. Peter of Blois (_Serm._ 25) describes schools for the novices as being in the west walk, and moral lectures delivered in that next the church. At Canterbury the monks' school was in the western ambulatory, and it was in the same walk that the novices were taught at Durham (Willis, _Monastic Buildings of Canterbury_, p. 44; _Rites of Durham_, p. 71). The other alleys, especially that next the church, were devoted to the studies of the elder monks. The constitutions of Hildemar and Dunstan enact that between the services of the church the brethren should sit in the cloister and read theology. For this purpose small studies, known as "carrols," i.e. a ring or enclosed space, were often found in the recesses of the windows. Of this arrangement there are examples at Gloucester, Chester and elsewhere. The use of these studies is thus described in the _Rites of Durham_:--"In every wyndowe" in the north alley "were iii pewes or carrells, where every one of the olde monkes had his carrell severally by himselfe, that when they had dyned they dyd resorte to that place of cloister, and there studyed upon their books, every one in his carrell all the afternonne unto evensong tyme. This was there exercise every daie." On the opposite wall were cupboards full of books for the use of the students in the carrols. The cloister arrangements at Canterbury were similar to those just described. New studies were made by Prior De Estria in 1317, and Prior Selling (1472-1494) glazed the south alley for the use of the studious brethren, and constructed "the new framed contrivances, of late styled carrols" (Willis, _Mon. Buildings_, p. 45). The cloisters were used not for study only but also for recreation. The constitutions of Archbishop Lanfranc, sect. 3, permitted the brethren to converse together there at certain hours of the day. To maintain necessary discipline a special officer was appointed under the title of _prior claustri_. The cloister was always furnished with a stone bench running along the side. It was also provided with a lavatory, usually adjacent to the refectory, but sometimes standing in the central area, termed the cloister-garth, as at Durham. The cloister-garth was used as a place of sepulture, as well as the surrounding alleys. The cloister was in some few instances of two stories, as at Old St Paul's, and St Stephen's chapel, Westminster, and occasionally, as at Wells, Chichester and Hereford, had only three alleys, there being no ambulatory under the church wall.

The larger monastic establishments had more than one cloister; there was usually a second connected with the infirmary, of which there are examples at Westminster Abbey and at Canterbury; and sometimes one giving access to the kitchen and other domestic offices.

The cloister was not an appendage of monastic houses exclusively. It was also attached to colleges of secular canons, as at the cathedrals of Lincoln, Salisbury, Wells, Hereford and Chichester, and formerly at St Paul's and Exeter. It is, however, absent at York, Lichfield, Beverley, Ripon, Southwell and Wimborne. A cloister forms an essential part of the colleges of Eton and Winchester, and of New College and Magdalen at Oxford, and was designed by Wolsey at Christ Church. These were used for religious processions and lectures, for ambulatories for the studious at all times, and for places of exercise for the inmates generally in wet weather, as well as in some instances for sepulture.

For the arrangements of the Carthusian cloisters, as well as for some account of those appended to the monasteries of the East, see ABBEY. (E. V.)

CLONAKILTY, a seaport and market town of Co. Cork, Ireland, in the south parliamentary division, at the head of Clonakilty Bay, 33 m. S.W. of Cork on a branch of the Cork, Bandon & South Coast railway. Pop. of urban district (1901), 3098. It was brought into prosperity by Richard Boyle, first earl of Cork, and was granted a charter in 1613; but was partly demolished on the occasion of a fight between the English and Irish in 1641. It returned two members to the Irish parliament until the union. In the 18th century there was an extensive linen industry. The present trade is centred in brewing, corn-milling, yarn and farm-produce. The harbour-mouth is obstructed by a bar, and there is a pier for large vessels at Ring, a mile below the town. The fisheries are of importance. A ruined church on the island of Inchdorey, and castles on Galley Head, at Dunnycove, and at Dunowen, together with a stone circle, are the principal antiquities in the neighbourhood.

CLONES, a market town of Co. Monaghan, Ireland, in the north parliamentary division, 64-1/2 m. S.W. by W. from Belfast, and 93-1/2 m. N.W. from Dublin by the Great Northern railway, on which system it is an important junction, the lines from Dublin, from Belfast, from Londonderry and Enniskillen, and from Cavan converging here. Pop. of urban district (1901), 2068. The town has a considerable agricultural trade, and there are corn mills and manufactures of agricultural implements. A former lace-making industry is extinct. The market-place, called the Diamond, occupies the summit of the slight elevation on which the town is situated. Clones was the seat of an abbey founded in the 6th century by St Tighernach (Tierney), to whom the Protestant parish church is dedicated. Remains of the abbey include a nave and tower of the 12th century, and a curious shrine formed out of a great block of red sandstone. Other antiquities are a round tower of rude masonry, 75 ft. high but lacking the cap; a rath, or encampment, and an ancient market cross in the Diamond.

CLONMACNOISE, one of the most noteworthy of the numerous early religious settlements in Ireland, on the river Shannon, in King's county, 9 m. S. of Athlone. An abbey was founded here by St Kieran in 541, which as a seat of learning gained a European fame, receiving offerings, for example, from Charles the Great, whose companion Alcuin the scholar received part of his education from the great teacher Colcu at Conmacnoise. Several books of annals were compiled here, and the foundation became the seat of a bishopric, but it was plundered and wasted by the English in 1552, and in 1568 the diocese was united with that of Meath. The most remarkable literary monument of Clonmacnoise is the Book of the Dun Cow, written about 1100, still preserved (but in an imperfect form) by the Royal Irish Academy, and containing a large number of romances. It is a copy of a much earlier original, which was written on the skin of a favourite cow of St Kieran, whence the name of the work. The full title of the foundation is the "Seven Churches of Clonmacnoise," and remains of all these are extant. The Great Church, though rebuilt by a chief named McDermot, in the 14th century, retains earlier remains in a fine west doorway; the other churches are those of Fineen, Conor, St Kieran, Kelly, Melaghlin and Dowling. There are two round towers; O'Rourke's, lacking the roof, but occupying a commanding situation on rising ground, is dated by Petrie from the early 10th century, and stands 62 ft. in height; and McCarthy's, attached to Fineen's church, which is more perfect, but rather shorter, and presents the unusual feature of a doorway level with the ground, instead of several feet above it as is customary. There are three crosses, of which the Great Cross, made of a single stone and 15 ft. in height, is splendidly carved, with tracery and inscriptions. It faces the door of the Great Church, and is of the same date. A large number of inscribed stones dating from the 9th century and after are preserved in the churches. There are further remains of the Castle and Episcopal palace, a fortified building of the 14th century, and of a nunnery of the 12th century. In the neighbourhood are seen striking examples of the glacial phenomenon of _eskers_, or gravel ridges.