clock with or without a train remoutoire ; only the pendulum will not stand so high, and the front end of the pallet arbor must he set in a cock like those of the striking flies, oil the front bar of the frame. And for a dead escapement, if there are large dials and no rernontoire, the pendulum should be longer and heavier than that which is quite sufficient for a gravity escapement. The rod of a wooden pendulum should be as thin as it can conveniently be made, and varnished, to prevent its absorbing moisture.
Dials and Hands.
The old established form of dial for turret clocks is a sheet of copper made convex, to preserve its shape ; and this is just the worst form which could have been contrived for it. For, in the first place, the minute-hand, being necessarily outside of the hour-hand, is thrown still farther off the minutes to which it has to point, by the convexity of the dial ; and consequently, when it is in any posi tion except nearly vertical, it is impossible to see accurately where it is pointing ; and if it is bent enough to avoid this eifect of parallax, it looks very ill. Secondly, a convex dial at a consider able height from the ground looks even more convex than it really is, because the lines of sight from the middle and the top of the dial make a smaller angle with the eye than the lines from the middle and the bottom, in proportion to the degree of convexity. The obvious remedy for these defects, is simply to make the dial concave instead of convex. As convex dials look more curved than they are, concave ones look less curved than they are, and in fact might easily be taken for flat ones, though the curvature is exactly the same as usual. Old convex dials are easily altered to concave, and the improvement is very striking where it has been done. There is no reason why the same form should not be adopted in stone, cement, slate, or cast-iron, of which materials dials are some times and properly enough made, with the middle part countersunk for the hour hand, so that the minute-hand may go close to the figures and avoid parallax. When dials are large, copper, or even iron or slate, is quite a useless expense, if the stonework is moder ately smooth, as most kinds of stone take and retain paint very well, and the gilding will stand upon it better than it often does on copper or iron.
The figures are generally made much too large. People have a pattern dial painted ; and if the figures are not as long as one-third of the radius, and therefore occupying, with the minutes, about two- thirds of the whole area of the dial, they fancy they are not large enough to be read at a distance ; whereas the fact is, the more the dial is occupied by the figures, the less distinct they are, and the more difficult it is to distinguish the position of the hands, which is what people really want to see, and not to read the figures, which may very well be replaced by twelve large spots. The figures, after all, do not mean what they say, as you read " twenty minutes to" something, when the minute-hand points to vm. The rule which has been adopted, after various experiments, as the best for the proportions of the dial, is this. Divide the radius into three, and leave the inner two-thirds clear and flat, and of some colour forming a strong contrast to the colour of the hands, black or dark blue if they are gilt, and white if they are black. The figures, if there are any, should occupy the next two-thirds of the remaining third, and the minutes be set in the remainder, near the edge, and with every fifth minute more strongly marked than the rest ; and there should not be a rim round the dial of the same colour or gilding as the figiires. The worst kind of dial of all are the things called skeleton-dials, which either have no middle except the stone work, forming no contrast to the hands, or else taking special trouble to perplex the spectator by filling up the middle with radiating bars. Where a dial cannot be put without interfering with the architecture, it is much better to have none, as is the case in many cathedrals and large churches, leaving the information to be given by the striking of the hours and quarters. This also will save something, perhaps a good deal, in the size and cost of the clock, and if it is one without a train remoutoire or gravity escape- Uient, will enable it to go better. The size of public dials is often rery inadequate to their height and the distance at which they are intended to be seen. They ought to be at least 1 foot in diameter for every 10 feet of height above the ground, and more whenever the dial will be seen far off; and this rule ought to be enforced on archi tects, as they are often not aware of it ; and indeed they seldom make proper provisions for the clock or the weights in building a tower, or, in short, know anything about the matter.
The art of illuminating dials cannot be said to be in a satisfactory state. Where there happens to be, as there seldom is, a projecting roof at some little distance below the dial, it may be illuminated by reflection, like that at the Horse Guards about the only merit which that superstition sly venerated and bad clock has ; and the same thing may be done in some places by movable lamp reflectors, like those put before shop windows at night, to be turned back against the wall during the day. It has also been proposed to sink the dial within the wall, and illuminate it by jets of gas pointing inwards from, a kind of projecting rim, like what is called in church windows a "hood-moiddiiig," carried all round. But it is a great objection to sunk dials, even of less depth than would be required here, that they do not receive light enough by day, and do not get their faces washed by the rain. The common mode of illumina tion is by making thelials either entirely, or all except the figures and minutes and a ring to carry them, of glass, either ground or lined in the inside with linen (paint loses its colour from the gas). The gas is kept always alight, but the clock is made to turn it nearly off and full on at the proper times by a 24-hour wheel, with pins set in it by hand as the length of the day variew. Self-acting apparatus has been applied, but it is somewhat complicated, and an unnecessary expense. But these dials always look very ill by day ; and it seems often to be forgotten that dials are wanted much more by day than by night ; and also, that the annual expense of lighting 3 or 4 dials far exceeds the interest of the entire cost of any ordinary clock. Sometimes it exceeds the whole cost of the clock annually. The use of white opaque glass with black figures is ver) superior to the common method. It is used in the great Westminster clock dials. It is somewhat of an objection to illuminating large dials from the inside, that it makes it impossible to counterpoise the hands outside, except with very short, and there fore very heavy, counterpoises. And if hands are only counterpoised inside, there is no counterpoise at all to the force of the wind, which is then constantly tending to kosen them on the arbor, and that tendency is aggravated by the hand itself pressing on the arbor one way as it ascends, and the other way as it descends ; and if a large hand once gets in the smallest degree loose, it becomes rapidly worse by the constant shaking. It is mentioned in Reid s book that the minute-hand of St Paul s cathedral, which is above 8 feet long, used to fall over above a minute as it passed from the left to the right side of xii, before it was counterpoised outside. In the conditions to be followed in the Westminster clock it was expressly required that "the hands be counterpoised externally, for wind as well as weight. " The long hand should be straight and plain, to distinguish it as much as possible from the hour hand, which should end in a "heart" or swell. Many clockmakers and architects, on the con trary, seem to aim at making the hands as like each other as they can ; and it is not uncommon to see even the counterpoises gilt, probably with the same object of producing apparent symmetry and the same result of producing real confusion.
The old fashion of having chimes or tunes played by machinery on church bells at certain hours of the day has greatly revived in the last few years, and it has extended to town halls, as also that of having very large clock bells, which had almost become extinct until the making of the Westminster clock. The old kind of chime machinery consisted merely of a large wooden ban-el about 2 feet in diameter with pins stuck in it like those of a musical box, which pulled down levers that lifted hammers on the bells. Generally there were several tunes " pricked " on the barrel, which had an endway motion acting automatically, so as to make a shift after eacli tune, and with a special adjustment by hand to make it play a psalm tune on Sundays. But though these tunes were very pleasing and popular in the places where such chimes existed they were generally feeble and irregular, because the pins and levers were not strong enough to lift hammers of sufficient weight for the large bells, and there were no means of regulating the time of dropping off the levers. Probably the last large chime work of this kind was that put up by Dent to play on 16 bells at the Royal Exchange in 1845, with the improvement of a cast-iron barrel and stronger pins than in the old wooden barrels.
A much improved chime machine has been introduced since, at first by an inventor named Imhoff, who sold Ms patent, or the right to use it, to Messrs Gillett and Bland of LYoydon, and also to Messrs Lund and Blockley of Pall Mall, who have both added further improvements of their own. The principle of it is this : instead of the hammers being lifted by the pins which let them off, they are lifted whenever they are down by an independent set of cam wheels of ample strength ; and all that the pins on the barrel have to do is to trip them up by a set of comparatively light levers or detents. Consequently the pins are as small as those of a barrel organ, and many more tunes can be set on the same barrel than in the old plan, and besides that, any number of barrels can be kept, and put in from time to time as you please ; so that you may have as many tunes as the peal of bells will admit. There are various provisions for regulating and adjusting the time, and the machinery is altogether of a very perfect kind for its purpose, but it must bo seen to be understood.
It is always necessary in chimes to have at least two hammers to each bell to enable a note to be repeated quickly. Some ambitious musicians determined to try " chords" or double notes struck at them, ine largest peaia ana cmmus wt "* -< cester cathedral, and the town halls of Bradford and Rochdale, and a still larger one is now making for Manchester, all by Gillett ano Bland. The clock at Worcester, which as yet ranks next to West- minster, was made by Mr Joyce of Whitchurch ; the others are by Gillett and Bland. At Boston church they have chimea m
