Part 7

To prevent the straining of the spring, a little contrivance called the stop-work is introduced. It consists of a piece of steel somewhat in the shape of a bayonet, which is so fixed and contrived that the last turn of the gut or chain on the fusee forces the stop into contact with a projection on the end of the fusee, which abutting against it, forms the check felt when the clock is wound up. On the same arbor with the fusee is fixed the main wheel, which with the before-described contrivance of click and ratchet, permits the turning of the fusee or winding-up of the clock, while it itself remains stationary. This wheel acts in the centre pinion (a pinion is a little wheel playing in the teeth of a larger wheel, and has six, eight, ten, or twelve teeth, or, as they are called, leaves), which is fixed to the centre arbor, and carries the minute hand. This pinion is so constructed in relation to the other parts of the clock as to make one revolution in an hour; the centre wheel being firmly riveted on the pinion, it must also revolve once an hour. The centre wheel acts into another pinion, which is called the third wheel pinion, upon the arbor or axle of which is securely fixed the third wheel, which again acts in the escape-pinion carrying the escapement-wheel. On the top of the back plate is firmly screwed the back cock, or the support of the pendulum, which is suspended from it by a flexible spring, as before described. This pendulum receives impulsion from the wheel-work by means of the crutch, a small part attached to the arbor of the pallets, and which projects downwards about three inches, parallel with the pendulum rod. To the lower part of the crutch is screwed or riveted at a right angle a piece of steel, in such a direction as to penetrate the pendulum rod, which has a slot or hole cut to receive it; impulsion is thus given to the pendulum. Between the frame and dial-plate is the motion work, consisting of three wheels; the first, called the minute wheel, is attached to the arbor of the centre wheel, which, it will be recollected, makes one revolution an hour, and acts in a wheel of the same size, whose axle carries a pinion serving to drive the hour wheel. This hour wheel is supported by a bridge screwed over the minute wheel. The dial is pinned on to the front plate; the hour hand is fixed on a socket communicating with the hour wheel, and the minute hand on the arbor of the centre wheel.

When a clock is intended to strike, a separate train of wheels has to be introduced into it,--one train of wheels serving to keep the time, and another train for the striking part. It may be as well to add that a greater amount of labour is required to make the striking than the going part of a clock.

+----------------------------------------------------------------------+ | [Illustration: Rack Striking Work.] | +----------------------------------------------------------------------+

There are only two kinds of striking parts now in use, and these are characterized by the terms 'Rack' striking work, and 'Count-wheel,' or 'Locking-plate,' striking work. The Rack striking work (see next page) is the best and safest ever introduced, because with it the clock may be made to strike any number of times within the hour. A, the minute wheel revolving in the direction of the arrow, and driving the wheel B, which is of the same size, and has the same number of teeth. C, a pin fixed in the wheel B, and acting on the lever D, which has its centre of motion in the point E. L, the click, the lower point of which acts in the teeth K of the rack M. S, the rack-spring, which acts upon the lower end of the rack, or, as it is called, the rack-tail, and brings it in contact with the snail P. Q and R are the jumper and its spring, by which the snail P, fastened to the star-wheel O, is kept in its place. Y, the centre of motion of the rack, on which it acts freely. In the wheel A is fixed a pin U, which, as the wheel A rotates, gradually forces before it a tooth of the star-wheel O, which carries with it the snail P, until at last the second step of the snail is opposite the rack-tail. While this is going on, the wheel B, driven by the wheel A, is advancing in the opposite direction, and, by means of the pin C, is pushing before it the end of the lever D. It is obvious that the other end, F, of the lever will be gradually raised, and this will lift the lower point of the click L out of the teeth of the rack. The latter being now free will yield to the action of the spring S, which will force its lower end into contact with the second step of the snail, and throw back the head of the rack to a corresponding extent. By this action the striking train of wheels is released, and the two wheels, G and I, seen in the upper part of our cut, begin to rotate, but are stopped by H, a pin that is caught by a stud which projects from the end F of the lever. As the wheel B advances, the pin C gradually frees itself from the long arm of the lever D, which drops by its own weight into its original position, and frees the wheels G and I, which immediately commence once more to rotate. At the centre of the wheel I is fixed the gathering pallet, that, as it revolves with the wheel, gathers up one by one the teeth of the rack, which is prevented from falling back by the lower end of the click L, and thus gradually draws it forward until the last tooth is reached, when the end of the gathering pallet abuts on the end of the rack head, and the train of wheels is once more at rest. It is obvious that for every tooth of the rack which is gathered up, there is one revolution of the wheel I, and this communicates with the tail of the hammer, causing at each revolution a blow on the bell. There is, as will be at once seen, an important connection between the various parts. When the second step of the snail is presented to the rack-tail, the head of the rack is thrown back a distance corresponding to the width of two of its teeth. This requires two revolutions of the gathering pallet to return it to its place; and these two revolutions of the pallet and the wheel which carries it govern the two blows on the bell which signify the hour. At three o'clock the third step of the snail will be presented to the hammer-tail, and so on.

On the next page is an illustration of the back part of a French Clock, as seen upon opening the door of the case. At the right hand side will be observed the count-wheel A, fitting tightly upon a prolonged square arbor of the second wheel in the train, and having twelve openings of unequal length around its outer edge, 1, 2, &c. Just above the wheel towards the right will also be seen the 'Dog,' or 'Detent,' F, which falls into these notches, and is a part of the locking similar to that which is represented at the stud and the pin H. So soon as the stud is lifted the pin becomes disengaged, the wheel-work revolves, and the count-wheel being firmly fixed to the prolonged arbor of one of those wheels, advances with it in the direction indicated by the arrow, the detent resting upon the plain part of the locking-wheel. When the required number of hours have struck, the notch approaches the detent, the gravity of which allows it to fall therein.

+----------------------------------------------------------------------+ | [Illustration: Back of French Clock.] | +----------------------------------------------------------------------+

In connection with this detent is also another projecting piece, which is carried inside the frame, and when it falls presents a broad surface to a pin fixed in the rim of one of the wheels. Thus the motion of the wheel-work is stayed until this piece is again lifted by the going parts from the pin, and held in that position by the outer rim of the locking-wheel A, until again the next notch is presented to the detent. When it falls, the stud is carried with it, against which the pin becomes engaged. The number of strokes depends on the distance which the count-wheel has to revolve before being stopped by the detent F. The chief objection to the locking-plate being used for striking, arises from the fact that, if ever the clock is allowed to run down, or if the clock gets otherwise stopped, it strikes wrong afterwards, until it has been properly re-set to the hour.

Clocks are made of all manner of shapes, patterns, and sizes, for all manner of places, positions, and persons.

BRACKET CLOCKS, which are intended to occupy but a small space, say on a staircase, or lobby, or landing, are sometimes made with extreme finish, care, and elegance, sometimes are simply plain and devoid of embellishment. They are constructed with or without striking work.

CHIME CLOCKS are a great addition to the attractions of a house. They are usually made to go eight or fifteen days; to strike the hours and quarters on four or eight bells or gongs.

MUSICAL CLOCKS are constructed so as to play several tunes at certain intervals with the greatest finish and perfection. The mechanism for time-keeping being easily disconnected from the musical mechanism, the latter may be stopped without any interference with the clock as a time-keeper.

CARRIAGE CLOCKS are made so as to be unaffected by the motion of the vehicle. They are usually of a small and squarish shape, enclosed in leather, so as to protect the case from scratches; but they vary in size,--measuring usually from four to seven inches high by two-and-a-half to four inches in breadth and the same in depth. Some are made without striking movement, some to strike hours, half-hours, and quarters, some with repeating work, and some with an alarm added to them.

+----------------------------------------------------------------------+ | [Illustration: Carriage Clock.] | +----------------------------------------------------------------------+

LIBRARY and DINING-ROOM CLOCKS are frequently seen decorated with highly elegant ornaments, in bronze, marble, ormolu, and with miniature figures, as well as objects of still life, but these clocks are usually not so conspicuously ornamental as those which are designed for the drawing-room.

SKELETON CLOCKS are so named from their movements being all bare and uncovered. When watches were comparative novelties it was not at all an uncommon desire on the part of their possessors to watch the operations of a mechanism which was regarded as wonderfully resembling life itself. Watch cases were consequently made of crystal, and were found strong and serviceable. In skeleton clocks the escapement is sometimes made a peculiarly interesting feature to the non-professional eye delighting in noting the amazing accuracy with which each piece of the mechanism works and combines to produce the result required.

REGULATOR CLOCKS are, as we have said, the most perfect time-pieces which can be manufactured.

TELL-TALE CLOCKS are of great service in securing the attention and watchfulness of persons left in care of premises or property. They are made with a number of pins projecting round the edge of the dial, and coming into contact once every quarter of an hour with a pin fixed at the top part of the dial, over the part which in an ordinary clock is occupied by XII. The dial revolves completely once every twelve hours, and presents one of the projecting pins to the index every quarter of an hour; the watchman should then be ready at hand to pull a cord, by means of which the projecting pin is pushed in; otherwise the dial shows the exact time of his absence and neglect of duty.

+----------------------------------------------------------------------+ | [Illustration: English Ormolu Clocks.] | | | | [Illustration: English Ormolu Clock, &c.] | | | | [Illustration: English Ormolu Clock, &c.] | | | | [Illustration: Tell-Tale Clock.] | +----------------------------------------------------------------------+

ELECTRICAL CLOCKS have been several times planned and made by different ingenious inventors, and obtained considerable notice, but they have not been hitherto as successful as was expected. Electricity has been applied to the direct movement of the pendulum itself, and subsequently to the raising a small weight to act upon the pendulum in the style of a gravity escapement. In perhaps the latest of these instruments, called a Magnetic Clock, an electromagnet was used to relieve the pendulum from the influence of the spring by which impulsion had been given, and to make the return or reflex vibration. Electric clocks are now seldom made; electric dials without any clock-movement in connection with them are made to show the standard time by means of a galvanic current sent from the Greenwich Observatory clock at intervals of a minute or half-minute it may be,--even as Electric Timeballs show to distant towns and out-ports, by means of such a current, the exact Greenwich time once a day.

The ELECTRO-CHRONOGRAPH is a new and useful invention for timing with great precision the quickest of events. It is applied to a central seconds clock with a dial three feet in circumference showing the hours, minutes, seconds and fifths of seconds. This clock erected in a prominent position, say on a raceground, and worked by electricity, enables the starter of a race to set the works in motion; by means of a tape held up at the winning post and connected with the batteries, the winner upon breasting the tape stops the hand of the clock.

* * * * *

The following simple directions will be found of great use in the management of a Clock:--

When the Clock is unpacked it should be carefully handled with a silk handkerchief or piece of tissue paper, to prevent the moisture of the hands soiling the case. Unscrew the bell and take it off, then put on the pendulum by passing it through the fork, and hang it upon the two small brass pins, _with the hook from you_. Screw on the bell with the convex part outwards, taking care that it does not touch the pendulum.

The stand or bracket should be both steady and level before the Clock is placed upon it; for, unless the Clock is quite in proper beat--that is, unless the beats or ticks occur at equal intervals, it cannot go regularly.

In order to set the Clock to the hour of the day, the minute-hand should be turned on carefully forward with the finger and thumb, the setter pausing as he reaches the XII. and the VI., to allow the Clock to strike each hour and half-hour.

If the striking should at any time be wrong, and it should strike the hour at the half-hour, or the half-hour at the hour, the error can be rectified by moving the minute-hand on to 5 minutes before the hour, or half-hour, and then back until it strikes.

Or, if it should strike a wrong hour--_e.g._, supposing the Clock should strike 3, and the hour-hand point at 7, then the hour-hand may be moved back to 3, and the Clock afterwards set to the hour of the day in the usual manner.

If, at any future time, the Clock should require regulating, the small steel square above the XII. is the regulator, and turning it a _little_ to the right (half-turn of key) will make the Clock go faster, and to the left, slower. This should be repeated until the desired effect is obtained.

The bell-stud, or arm to which the bell is screwed, is purposely made of soft metal, so that it can be bent up or down so as to obtain a heavy or light blow of the hammer as may be desired.

Both squares in the dial should be wound once a week.

TURRET CLOCKS.

A Church tower without a clock and bells seems an unfurnished edifice, which must be fitted and filled before it can serve the purpose for which it was built;--like a form without life, a body without a soul. A good Church clock is useful to everybody; it is the friendly monitor alike of rich and poor,--the regulator of every private time-piece,--the standard of time for a whole parish or township. By it the artisan or mechanic trudges off to his daily labour; by it the tradesman opens and closes his shop; by it the schoolboy is admonished as 'with shining morning face he creeps like snail unwillingly to school;' by it the law itself regulates its penalties,--(enacting, as it does, house-breaking between nine at night and six in the morning to be the heavier crime of burglary;)--by it, in a word, are all the multifarious transactions of everyday life more or less regulated and measured, and when the church clock stops, it produces a social discomfort and anarchy throughout a whole neighbourhood, to an extent scarcely credible. A good public clock is a benefit to all,--a faulty one is a general nuisance and a continual source of irritation. A public clock is in its way as necessary as the public highway, the public market, the public law itself. It is the product and the symbol of advanced civilization, the one everwakeful watchman and trusty friend of all, by whose chimes the sleepless merchant has often planned his ventures or sighed o'er apprehended losses and dangers; the student busied with researches has consumed the midnight oil; the sick have counted their hours of pain, longing in the night for the dawn, in the daytime for the night. On the other hand, when one like Mr Justice Shallow is reminded of the mad days of his London youth, he very aptly associates them with the Bacchanalian memories which Falstaff appeals to,--'We have heard the chimes at midnight.'

To have lived 'where bells have knoll'd to church' was according to Shakspeare to have been blessed by humanizing influences comparable with those produced by having--

'Sat at good men's feasts, and wiped our eyes Of drops that sacred pity has engendered.'

Cowper can find no better words to describe the utter desolation of the island where the shipwrecked Selkirk bemoaned his absolute solitude 'out of humanity's reach,' than by putting into his mouth the language--

'But the sound of a church-going bell These valleys and rocks never heard, Never sigh'd at the sound of a knell, Nor smiled when a Sabbath appear'd.'

In our everyday experience we can each testify to the truthfulness of the poet who points to the close association which exists in most minds between the church clock and the varying times and seasons, with their different joys and sorrows, and we can most of us say, with Southey,--

'I love the bell that calls the poor to pray, Chiming from village church its cheerful sound, When the sun smiles on labour's holy-day And all the rustic train are gather'd round, Each deftly dizen'd in his Sunday's best, And pleased to hail the day of piety and rest.

And when, dim shadowing o'er the face of day, The mantling mists of eventide rise slow, As through the forest gloom I wend my way, The minster curfew's sullen voice I know, And pause, and love its solemn toll to hear, As made by distance soft it dies upon the ear.'

It is but a short step from the sentimental consideration of such reminiscences to the practical inquiry how is the public time kept, and yet it is one which probably is seldom taken with a view to more or less thorough investigation. Without traversing the distance which divides us from that antique time when Archimedes measured the shadows of the Pyramids by his walking-stick, or when the 'dial of Ahaz' was constructed as one of the first of historical time-measurers, we can discover the principles upon which an instrument such as a thoroughly serviceable public clock of the present time, with all the newest improvements both in time-keeping and in wearing qualities, should be produced.

It is of some consequence, in the first place, to know that the introduction of steam-machinery has added to the accuracy of clockwork and at the same time considerably diminished its cost; fifty or sixty years ago there would have been charged as much as £800 for a turret clock inferior to that which may now be procured for £150; and the result is to be seen in the largely increased numbers of public time-pieces. It is obvious, however, that there is none the less need of care in the choice of a Clockmaker, for upon his skill and trustworthiness will depend whether the money be well spent or not, and whether the instrument furnished by him prove to be valuable and serviceable. It is not a purchase wherein the buyer can usually of himself judge of the merits of his bargain, he must rely upon the reputation established by previous works of the same kind. If the Clockmaker be not merely a clock-seller (as is too often the case, for Turret Clockmakers are but few), he will be able to point to similar instruments made and set up by himself in different towns and cities, in proof of his ability, but there will still be a necessity for explaining to the purchaser the chief points upon which the accuracy of such a time-keeper must depend.