tion of some of the foreign ones on above 40 small bells, which were added for that purpose to the eight of the peal; but they are not successful, and it is stated in Sir E. Beckett's book on clocks and bells, that he warned them that the large and small bells would not harmonize, though either might be used separately. Other persons have attempted chimes on hemispherical bells, like those of house clocks; but they also are a failure for external bells to be heard at a distance. This however belongs rather to the subject of bells; and we must refer to that book for all practical information about them.

TEETH OF WHEELS.

Before explaining the construction of the largest clock in the world it is necessary to consider the shape of wheel teeth suitable for different purposes, and also of the cams requisite to raise heavy hammers, which had been too much neglected by clockmakers previously. At the same time we are not going to write a treatise on all the branches of the important subject of wheel-cutting; but, assuming a knowledge of the general principles of it, to apply them to the points chiefly involved in clock-making. The most comprehensive mathematical view of it is perhaps to be found in a paper by the astronomer royal in the Cambridge Transactions many years ago, which is further expanded in Professor Willis's Principles of Mechanism. Respecting the latter book, however, we should advise the reader to be content with the mathematical rules there given, which are very simple, without attending much to those of the odontograph, which seem to give not less but more trouble than the mathematical, and are only approximate after all, and also do not explain themselves, or convey any knowledge of the principle to those who use them.

For all wheels that are to work together, the first thing to do is to fix the geometrical, or primitive, or pitch circles of the two wheels, i.e., the two circles which, if they rolled perfectly together, would give the velocity-ratio you want. Draw a straight line joining the two centres; then the action which takes place between any two teeth as they are approaching that line is said to be before the line of centres; and the action while they are separating is said to be after the line of centres. Now, with a view to reduce the friction, it is essential to have as little action before the line of centres as you can; for if you make any rude sketch, on a large scale, of a pair of wheels acting together, and serrate the edges of the teeth (which is an exaggeration of the roughness which produces friction), you will see that the further the contact begins before the line of centres, the more the serration will interfere with the motion, and that at a certain distance no force whatever could drive the wheels, but would only jam the teeth faster; and you will see also that this cannot happen after the line of centres. But with pinions of the numbers generally used in clocks you cannot always get rid of action before the line of centres; for it may be proved (but the proof is too long to give here), that if a pinion has less than 11 leaves, no wheel of any number of teeth can drive it without some action before the line of centres. And generally it may be stated that the greater the number of teeth the less friction there will be, as indeed is evident enough from considering that if the teeth were infinite in number, and infinitesimal in size, there would be no friction at all, but simple rolling of one pitch circle on the other. And since in clock-work the wheels always drive the pinions, except the hour pinion in the dial work, and the winding pinions in large clocks, it has long been recognized as important to have high numbered pinions, except where there is a train remontoire, or a gravity escapement, to obviate that necessity.

And with regard to this matter, the art of clock-making has in one sense retrograded; for the pinions which are now almost universally used in English and French clocks are of a worse form than those of several centuries ago, to which we have several times alluded under the name of lantern pinions, so called from their resembling a lantern with upright ribs. A sketch of one, with a cross section on a large scale, is given at fig. 24. Now it is a property of these pinions, that when they are driven, the action begins just when the centre of the pin is on the line of centres, however few the pins may be; and thus the action of a lantern pinion of 6 is about equal to that of a leaved pinion of 10; and indeed, for some reason or other, it appears in practice to be even better, possibly from the teeth of the wheel not requiring to be cut so accurately, and from the pinion never getting clogged with dirt. Certainly the running of the American clocks, which all have these pinions, is remarkably smooth, and they require a much smaller going weight than English clocks; and the same may be said of the common "Dutch," i.e., German clocks. It should be understood, however, that as the action upon these pinions is all after the line of centres when they are driven, it will be all before the line of centres if they drive, and therefore they are not suitable for that purpose. In some of the French clocks in the 1851 Exhibition they were wrongly used, not only for the train, but for winding pinions; and some of them also had the pins not fixed in the lantern, but rolling,-a very useless refinement, and considerably diminishing the strength of the pinion. For it is one of the advantages of lantern pinions with fixed

pins, that they are very strong, and there is no risk of their being broken in hardening, as there is with common pinions. The fundamental rule for the tracing of teeth, though very simple, is not so well known as it ought to be, and therefore we will give it, premising that so much of a tooth as lies within the pitch circle of the wheel is called its root or flank, and the part beyond the pitch circle is called the point, or the curve, or the addendum; and moreover, that before the line of centres the action is always between the flanks of the driver and the points of the driven wheel or runner (as it may be called, more appropriately than the usual term follower); and after the line of centres, the action is always between the points of the driver and the flanks of the runner. Consequently, if there is no action before the line of centres, no points are required for the teeth of the runner.

a

Runner

X

In fig. 23, let AQX be the pitch circle of the runner, and ARY that of the driver; and let GAP be any curve whatever of smaller curvature than AQX (of course circle is always the kind of curve used); and QP the curve which is traced out by any point P in the generating circle GAP, as it rolls in the pitch circle AQX; and again let RP be the curve traced by the point P, as the generating circle GAP is rolled on the pitch circle ARY; then RP will be the form of the point of a tooth on the driver ARY, which will drive with uniform and proper motion the flank QP of the runner; though not without some friction, because that can only be done with involute teeth, which are traced in a different way, and are subject to other conditions, rendering them practically useless for machinery, as may be seen in Professor Willis's book. If the motion is reversed, so that the runner becomes the driver, then the flank QP is of the proper form to drive the point RP, if any action has to take place before the line of centres.

G

Driver

Fig. 23.

R

And again, any generating curve, not even necessarily the same as before, may be used to trace the flanks of the driver and the points of the runner, by being rolled within the circle ARY, and on the circle AQX.

Driver

R

Now then, to apply this rule to particular cases. Suppose the generating circle is the same as the pitch circle of the driven pinion itself, it evidently cannot roll at all; and the tooth of the pinion is represented by the mere point P on the circumference of the pitch circle; and the tooth to drive it will be simply an epicycloid traced by rolling the pitch circle of the pinion on that of the wheel. And we know that in that case there is no action before the line of centres, and no necessity for any flanks on the teeth of the driver. But inasmuch as the pins of a lantern pinion must have some thickness, and cannot be mere lines, a further process is necessary to get the exact form of the teeth; thus if RP, FIG. 24.-Lantern Pinion. fig. 24, is the tooth that would drive a pinion with pins of no sensible thickness, the tooth to drive a pin of the thickness 2 Pp must have the width Pp or Rr gauged off it all round. This, in fact, brings it very nearly to a smaller tooth traced with the same generating circle; and therefore in practice this mode of construction is not much adhered to, and the teeth are made of the same shape, only thinner, as if the pins of the pinion had no thickness. Of course they should be thin enough to allow a little shake, or "back-lash," but in clock-work the backs of the teeth never come in contact at all.

Next suppose the generating circle to be half the size of the pitch. circle of the pinion. The curve, or hypocycloid, traced by rolling this within the pinion, is no other than the diameter of the pinion and consequently the flanks of the pinion teeth will be merely radii of it, and such teeth or leaves are called radial teeth; and they are far the most common; indeed, no others are ever made (except lanterns) for clock-work. The corresponding epicycloidal points of

both the striking parts

RUNNER

A

C

Fig. 25.

DRIVER

the great wheel of the train and the great winding-wheel on the other end of the barrel are about the same size; but in the train the wheel drives, and in winding the pinion drives. And therefore in the train the pinion-teeth have their points cut off, and wheel-teeth have their points on, as on the right side of fig. 25, and in the winding-wheels the converse; and thus in both cases the action is made to take place in the way in which there is the least friction. Willis gives the following table, "derived organically" (i.e., by actual trial with large models), of the least numbers which will work together without any action before the line of centres, provided there are no points to the teeth of the runner, assuming them to be radial teeth, as usual :

Driver......... 54 30 24 20 17 15 14 13 12 11 10 9 8 7 6
Runner........11 12 13 14 15 16 17 18 19 21 23 27 35 32 176

In practice it is hardly safe to leave the driven teeth without points, unless the numbers slightly exceed these; because, if there is any irregularity in them, the square edges of those teeth would not work smoothly with the teeth of the driver. Sometimes it happens that the same wheel has to drive two pinions of different numbers. It is evident that, if both are lanterns, or both pinions with radial teeth, they cannot properly be driven by the same wheel, because they would require teeth of a different shape. It is true that on account of the greater indifference of lantern pinions to the accuracy of the teeth which are to drive them, the same wheel will drive two pinions of that kind, differing in the numbers in the ratio of even 2 to 1, with hardly any sensible shake; but that would not be so with radial pinions, and of course it is not correct. Accordingly, in clocks with the spring remontoire, as in fig. 21, where the scape-wheel or remontoire pinion is double the size of the fly pinion, the larger one is made with radial teeth and the smaller a lantern, which makes the same wheel teeth exactly right for both. In clocks of the same construction as fig. 22, and in the Westminster clock, there is a case of a different kind, which cannot be so accommodated; for there the great wheel has to drive both the second wheel's pinion of 10 or 12, and the hour-wheel of 40 or 48; the teeth of the great wheel were therefore made to suit the lantern pinion, and those of the hour-wheel (i.e., their flanks) then depend on those of the great wheel, and they were accordingly traced by rolling a generating circle of the size of the lantern pinion on the inside of the pitch circle of the hour-wheel; the result is a tooth thicker at the bottom than usual. These are by no means unnecessary refinements; for if the teeth of a set of wheels are not properly shaped so as to work smoothly and regularly into each other, it increases their tendency to wear out in proportion to their inaccuracy, besides increasing the inequalities of force in the train. Sometimes turret clocks are worn out in a few years from the defects in their teeth, especially when they are made of brass or soft gun-metal.

In the construction of clocks which have to raise heavy hammers it is important to obtain the best form for the cams, as pins are quite unfit for the purpose. The conditions which are most important are that the action should begin at the greatest advantage, and therefore at the end of the lever, that when it ceases the face of the lever should be a tangent to the cam at both their points, and that in no part of the motion should the end of the lever scrape on the cam. In the common construction of clocks the first condition is deviated from as far as possible, by the striking pins beginning to act at some distance from the end of the lever; and consequently, at the time when the most force is required to lift the hammer there is the least given, and a great deal is wasted afterwards. The construction of curve for the cams, which is the most perfect mathematically, is that which is described in mathematical books under the name of the tractrix. But there are such practical difficulties in describing it that it is of no use. It should be observed that, in a well-known book with an appropriate name (Camus on the Teeth of Wheels), a rule for drawing cams has been inserted by some translator, which is quite wrong. It may be

proved that epicycloidal cams described as follows are so nearly of the proper mathematical form that they may be used without any sensible error. Let r be the radius of the circle or barrel on which the cams are to be set theoretically, i.e., allowing nothing for the clearance which must be cut out afterwards, for fear the lever should scrape the back of the cams in falling; in other words, r is the radius of the pitch circle of the cams. Call the length of the lever . Then the epicycloidal cams may be traced by rolling on the pitch circle a smaller one whose diameter is √r2+12 -r. Thus, if is 4 inches and r 8 inches (which is about the proper size for an 18-inch striking wheel with 20 cams), the radius of the tracing circle from the cams will be 0.9 inch. The advantage of cams of this kind is that they waste as little force as possible in the lift, and keep the lever acting upon them as a tangent at its point the whole way; and the cams themselves may be of any length according to the angle through which you want the lever to move.

Most people however prefer dealing with circles, when they can, instead of epicycloids; and drawing by compasses is safer than calculating in most hands. We therefore give another rule, sug gested by Mr E. J. Lawrence, a member of the horological jury in the 1851 Exhibition, which is easier to work, and satisfies the principal conditions stated just now, though it wastes rather more in lift than the epicycloidal curve; and the cams must not have their points cut off, as epicycloidal ones may, to make the lever drop off sooner; because a short cam has to be drawn with a different radius from a long one, to work a lever of any given length. But, on the other hand, the same curve for the cams will suit a lever of any length, whereas with epicycloidal cams you must take care to put the centre or axis of the lever at the exact distance from the centre of the wheel for which the curve was calculated-an easy enough thing to do, of course, but for the usual disposition of workmen to deviate from your plans, apparently for the mere pleasure of doing wrong. It is astonishing how, by continually making one machine after another, with a little deviation each time, the thing gradually assumes a form in which you can hardly recognise your original design at all. The prevention of this kind of blundering is one of the many advantages of making machines by machinery, for which no machine offers more facilities than clocks, and yet there is none to which it is less applied.

In fig. 26 let CA be a radius of the wheel, L in the same straight line the centre of the lever, and AB the space of one cam on the pitch circle of the cams, A being a little below the line of centres; AP is the arc of the lever. Draw a tangent to C the two circles at A, and a tangent to the cam circle at B; then T, their point of intersection, will be the centre of the circle which is the

Fig. 26.

A

face of the cam BP; and TB also =TA, which is a convenient test of the tangents being rightly drawn. The action begins at the point of the lever, and advances a little way up, but recedes again to the point, and ends with the lever as a tangent to the cam at P. The backs of the cams must be cut out rather deeper than the circle AP, but retaining the point P, to allow enough for clearance of the lever, which should fall against some fixed stop or banking on the clock-frame, before the next cam reaches it. The point of the lever must not be left quite sharp, for if it is, it will in time cut off the points of the cast-iron cams.

OIL FOR CLOCKS.

We will add a few words on the subject of oil for clocks. Olive. oil is most commonly used, sometimes purified in various ways, and sometimes not purified at all. We believe, however, that purified animal oil is better than any of the vegetable oils, as some of them are too thin, while others soon get thick and viscid. For turret clocks and common house clocks, good sperm oil is fine enough, and is probably the best. For finer work the oil requires some purifi cation. Even common neat's foot oil may be made fine and clear by the following method. Mix it with about the same quantity of water, and shake it in a large bottle, not full, until it becomes like a white soup; then let it stand till fine oil appears at the top, which may be skimmed off; it will take several months before it has all separated-into water at the bottom, dirt in the middle, and fine oil at the top. And it should be done in cold weather, because heat makes some oil come out as fine, which in cold would remain among the dirty oil in the middle, and in cold weather that fine oil of hot weather will become muddy. There are various vegetable oils sold at tool-shops as oil for watches, including some for which a prize medal was awarded in the Exhibition, but not by any of the mechanical juries; we have no information as to the test which was

THE WESTMINSTER CLOCK,

It is unnecessary to repeat the account of the long dispute between the Government, the architect of the House of Parliament, the astronomer royal, Sir E. Beckett, and some of the London clockmakers, which ended in the employment of the late E. J. Dent and his successor F. Dent from the designs and under the superintendence of Sir E. Beckett, as the inscription on it records The fullest account of these was given in the 4th and 5th editions of the Treatise on Clocks, and we shall now only describe its construction. Fig. 27 is a front elevation or section lengthwise of the clock. The frame is 16 feet long and 5 wide, and it rests on two iron plates lying on the top of the walls of the shaft near the middle of the tower, down which the weights descend. That wall reaches up to the bell chamber, and those iron plates are built right through it, and so is the great cock which carries the pendulum. The clock room is 28 feet x 19, the remaining 9 of the square being occupied by the staircase and an air-shaft for ventilating the whole building. The going part of the clock, however, not requiring such a long barrel as the striking parts, which have steel wire ropes 55 inch thick, is shorter than they are, and is carried by an intermediate bar or frame bolted to the cross bars of the principal frame. The back of them is about 24 feet from the wali, to leave room for a man behind, and the pendulum cock is so made as to let his head come within it in order to look square at the escapement. The escapement is the double three legs (fig. 13), and the length of the teeth or legs is 6 inches. The drawing represents the wheels (except the bevelled wheels leading off to the dials) as mere circles to prevent

principal ones are inserted and require no further notice. Their size can be taken from the scale; the great wheels of the striking parts are 24 and of the going part 2 inches thick, and all the wheels are of cast-iron except the smaller ones of the escapement, which are brass, but are painted like the iron ones.

The maintaining power for keeping the clock going while winding is peculiar and probably unique. None of those already described could have kept in gear long enough, maintaining sufficient force all the time, as that part takes 10 minutes to wind, even if the man does not loiter over it. This is managed without a single extra wheel beyond the ordinary winding pinion of large clocks. The winding wheel on the end of the barrel is close to the great wheel, and you see the pinion with the winding arbor in the oblique piece of the front frame of the clock. Consequently that arbor is about 6 feet long, and a little movement of its back end makes no material obliquity in the two bushes; i.e., it may go a little out of parallel with all the other arbors in the clock without any impediment to its action. Its back pivot is carried, not in a fixed bush, but in the lower end of a bar a little longer thanthe great wheel's radius, hanging from the back of the great arbor; and that bar has a spring click upon it which takes into ratchet teeth cast on the back of the great wheel. When the great wheel is turning, and you are not winding, the ratchets pass the click as usual, but as soon as you begin to wind the back end of the winding arbor would rise but for the click catching those teeth, and so the great wheel itself become the fulcrum for winding for the time. After the winding has gone a few minutes a long tooth projecting from the back of the arbor catches against a stop, because that end of the hanging bar and pinion have all risen a little with the motion of the great wheel.

FIG. 27.-Section of

Then the man is obliged to turn the handle back a little, which lets down the pinion, &c., and the click takes up some lower teeth; and so if he chooses to loiter an hour over the winding he can do no harm. The winding pinion "pumps" into gear and out again as usual. The going part will go 8 days, to provide for the possible forgetting of a day in winding. The weight is about 160 ib; but only one-14th of the whole force of that weight is requisite to drive the pendulum, as was found by trial; the rest goes in overcoming the friction of all the machinery, including a ton and a half of hands and counterpoises, and in providing force enough to drive them through all weathers, except heavy snows, which occasionally accumulate thick enough on several minute hands at once, on the left side of the dials, to stop the clock, those hands being 11 feet long. For the dials are 223 feet in diameter, or contain 400 square feet each, and there are very few rooms where such a dial could be painted on the floor. They are made of iron framing filled in with opal glass. Each minute is 14 inches wide. The only larger dial in the world is in Mechlin church, which is 40 feet wide; but it has no minute hand, which makes an enormous difference in the force required in the clock. They are completely walled off from the clock-room by a passage all round, and there are a multitude of gas lights behind them, which are lighted by hand, though provision was originally made in the clock for doing it automatically. The hour hands go so slow that their weight is immaterial, and were left as they were made of gun metal under the architect's direction; but it was impossible to have minute hands of that construction and weight without injury to the clock, and so they were removed by Sir E. Beckett, and others made of copper tubes, with a section composed of two circular arcs put together, and are consequently very stiff, while weighing only 28 Ib. The great weight is in the wheels, tubes, and counterpoises. The minute hands are partly counterpoised outside, making their total length 14 feet, to relieve the strain upon

Westminster Clock. their arbors. They all run on friction wheels imbedded in the larger tubes 5 inches wide, which carry the hour hands, which themselves run on fixed friction wheels.

There is nothing peculiar in the quarter striking part except its size, and perhaps in the barrel turning in an hour and a half, i.e., in three repetitions of the five chimes already_described. The cams are of wrought iron with hard steel faces. Each bell has two hammers, which enables the cams to be longer and the pressure on them less. The hour-striking wheel has ten cams 24 in. wide cast on it; but those cams have solid steel faces screwed on them. All this work was made for a hammer of 7 cwt., lifted 13 inches from the bell, i.e., about 9 inches of vertical lift. The hammer was reduced to 4 cwt. after the partial cracking of the bell. The rod from the lever to the hammer is made of the same wire rope as the weight ropes, and the result is that there is no noise in the room while the clock is strik ing. The lever is 5 feet 4 inches long, and strikes against the buffer spring shown in the drawing, to prevent concussion on the clock-frame, of which you cannot feel the least. The quarter hammer levers have smaller springs for the same purpose, and the stops of the striking part are also set on springs instead of rigid as usual. The flies, for which there was not room in the drawing, are near the top of the room and are each 2 feet 4 inches square. They make a considerable wind in the room when revolving. The only noise made in striking is their running on over their ratchets when the striking stops. Each striking weight is a ton and a half--or was before the great hammer was reduced. They take 5 hours to wind up, and it has to be done twice a week, which was thought better than making the parts larger and the teeth more numerous and the weights twice as much, to go a week, and of course the winding must have taken twice as long, as it was adapted to what a man can do continuously for some hours. Con sequently it was necessary to contrive something to stop the man

winding just before each time of striking. And that is done by a lever being tipped over by the snail at that time, which at once stops the winding. When the striking is done the man can put the lever up again and go on. The loose winding wheels are not pumped in and out of gear as usual, being too heavy, but one end of the arbor is pushed into gear by an eccentric bush turned by the oblique handle or lever which you see near the upper corner of each striking part, and they can be turned in a moment. They are held in their place for gear by a spring catch to prevent any risk of slipping out. Moreover the ropes themselves stop the winding when the weights came to the top, pretty much as they do in a spring clock or a watch, though not exactly.

The mode of letting off the hour striking is peculiar, with a view to the first blow of the hour being exactly at the 60th second of the 60th minute. It was found that this could not be depended on to a single beat of the pendulum, and probably it never can in any clock, by a mere snail turning in an hour, unless it was of a very inconvenient size. Therefore the common snail only lets it off partially, and the striking stop still rests against a lever which is not dropped but tipped up with a slight blow by another weighted lever resting on a snail on the 15-minute wheel, which moves more exactly with the escapement than the common snail lower in the train. The hammer is left on the lift, ready to fall, and it always does fall within half a second after the last beat of the pendulum at the hour. This is shown in fig. 28, where BE is the spring stop noticed above, and P the ordinary first stop on the long lifting lever PQ (which goes on far beyond the reach of this figure to the hour snail). The second or warning stop is CD, and BAS is the extra lever with its heavy end at S on the 15-minute snail. When that falls the end B tips up CD with certainty by the blow, and then the striking is free. The first, second, and third quarters begin at the proper times; but the fourth quarter chimes begin about 20 seconds before the hour.

The clock reports its own rate to Greenwich Observatory by galvanic action twice a day, i.e., an electric circuit is made and broken by the pressing together of certain springs at two given hours. And in this way the rate of the clock is ascertained and recorded, and the general results published by the astronomer royal in his annual report. This has been for some years so remarkably uniform, that the error has only reached 3 seconds on 3 per cent. of the days

The original stipulation in 1845 was that the rate should not vary more than a second a day-not a week; and this was pronounced impossible by Mr Vulliamy and the London Company of Clockmakers, and it is true that up to that time no such rate had ever been attained by any large clock. In 1851 it was by the above. mentioned clock, now at King's Cross Station, by means of the train remontoire, which was then intended to be used at Westminster, but was superseded by the gravity escapement.

The great hour bell, of the note E, weighs 13 tons and is 9 feet diameter and 9 inches thick. The quarter bells weigh respectively 78, 33, 26, and 21 cwt.; with diameters 6 feet, 41, 4, and 3 feet 9 inches, and notes B, E, F sh. and G sh. The hammers are on double levers embracing the bells, and turning on pivots pro-" jecting from the iron collars which carry the mushroom shaped tops of the bells. The bells, including £750 for recasting the first great hell, cost nearly £6000, and the clock £4080. The bell frame, which is of wrought iron plates, and the dials and hands, all provided by the architect, cost £11,934-a curious case of the accessories costing more than the principals. (E. B.)

CLOISTER (Latin, claustrum; French, cloître; Italian, chiostro; Spanish, claustro; German, kloster). The word "cloister," though now restricted to the four-sided enclosure, surrounded with covered ambulatories, usually attached to conventual 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 our earlier 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 " kloster-gang," or "kreuz-gang." In French, as with us, the word cloître 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 chapterhouse 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 dayrooms 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 (ABBEY, vol. i. p. 12). 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 Alban's seems to have been deficient in ambulatories till the abbacy of Robert of Gorham, 11511166, when the eastern walk was erected. This, as was often the case with the earliest ambulatories, was of wood covered with a pentice roof. 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 with us 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, "than which no building in this style, perhaps, has been so often drawn or so much admired" (Fergusson); and those of Aix, Fontifroide, 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 Mr 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 frescos invaluable in the history of art by Orgagna, 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 feet 6 inches in length, 137 feet 10 inches in breadth, while each ambulatory is 34 feet 6 inches wide by 46 feet high.

The cloister of a religious house was the scene of a large part of the life of the inmates of a monastery. When not in church, refectory, or dormitory, or engaged in manual labour, the monks were usually to be found here. The north walk of the cloister of St Gall appears to have served as the chapter-house. The cloister 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, from their square shape, were often found in the recesses of the windows. Of this arrangement we have examples at Gloucester, Chester (recently restored), and elsewhere. The use of these studies is thus described in the Rites of Durham :-" In every wyndowe " in the north alley were i 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 (1472-94) 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 cloistergarth 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 we have 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. We find it 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 of St Mary's, Winchester, and New 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 the article ABBEY. (E. V.)

CLONMEL, a parliamentary and municipal borough of Ireland, in the province of Munster, partly in the south riding of Tipperary and partly in Waterford county, 104 miles south-west from Dublin. It is built on both sides of the Suir, and also occupies Moore and Long Islands, which are connected with the mainland by three bridges. The principal buildings are the parish church, two Romar. Catholic churches, a Franciscan friary, two convents, an endowed school dating from 1685, a model school under the