Part 5

From the time when the first Nuremberg egg-watch was produced, there has always been noticeable an endeavour to make pocket time-pieces more and more small and portable so far as they could be made so consistently with their durability. Sometimes the love of very minute workmanship has been carried to an extreme, but toy-watches of eccentric shapes and patterns are but the few exceptions to the general rule, which has settled that usefulness and convenience are best provided for within certain moderate sizes, and that of all shapes the round and flat are the most easily carried. The great object of the watch-maker's ambition is to produce a time-keeper minutely accurate, and yet not so delicately constructed that it cannot withstand the rough usage to which even moderately careful wearers subject it.

It has been estimated that the manufacture of and trade in watches annually in England, France, Switzerland, and America, amount to over £5,000,000 per ann.; and that in Switzerland alone there are 38,000 persons, one-third of whom are women, engaged in the manufacture. It is probable that even the immense number of new watches thus annually produced barely exceeds the growing requirements of the people, who, as they increase in intelligence and receive higher wages, soon learn the advantage of personally possessing a pocket time-keeper, and make it accordingly their first ambition to purchase one. The Watch Clubs which are formed in the various towns and rural districts throughout the kingdom enable this desire to be gratified at but small pecuniary inconvenience, inasmuch as payment is thus made in small instalments at fixed intervals, and the watch is bought with sums which might have been spent thoughtlessly and to no permanent benefit. This first lesson in thrift having been well learnt, and the result being so palpably beneficial to those who exercise it, has often laid the basis of a regular habit of economy.

The motive power in the watch is derived, not as in the clock from weights, but from a spiral spring called THE MAINSPRING, set in a drum or barrel, and any inequality in the pressure of the spring is fatal to regular time-keeping. A highly tempered and finished spring is a primary requisite in watch-making; in order to provide for the uniform transmission of motive power from the barrel throughout the train to the escapement, the fusee and chain are used, the fusee being a hollow-sided cone, and the chain round it. When the spring is wound up its force is of course greatest, for the chain is then acting on the smallest end of the fusee. The proportions of the barrel to the centre wheel, and the size of the teeth in that wheel, have all to be carefully planned, and adjusted to one another, and these all again to the moving of the hands upon the dial.

The ESCAPEMENT is one of the most important parts of the mechanism of a watch. It may be one of either of the following.

+----------------------------------------------------------------------+ | [Illustration: Verge Escapement.] | +----------------------------------------------------------------------+

The _Verge_ escapement, as applied to Watches, will be seen annexed, A, part of the balance; _b_, the verge body; C, C, the pallets; D, the escape-wheel; E, escape-wheel pinion. The verge or arbor B of the balance has two pallets, C, C, which stand out at right angles, so as to be acted on alternately by the sloping teeth in the opposite sides of the crown or escapement-wheel, C.

The _Horizontal_ escapement, on the following page, so called because of the escape-wheel acting horizontally to the axis of the balance. This invention was perfected by Graham, after the death of the inventor, his master and friend, Thomas Tompion. _a_, the escape-wheel, having pins or stems rising from it, on the tops of which are teeth of a wedgelike form, of such a length as to permit little freedom within and without the cylinder _b_, which is firmly fixed to the balance _c_. Although _b_ is one piece, the two edges of the hollow part serve as distinct pallets, inasmuch as they receive alternately, during each vibration of the balance, an impulse from the curved outer edge of each tooth in succession; and as the wedge-shaped tooth passes from the pallet, the coming tooth falls on to the circular part of the cylinder, and there remains until the return of the balance, when that tooth which had previously rested on the circular portion of the cylinder, comes upon the edge or pallet, gives impulsion to the balance _c_, and falls upon the concave portion of the cylinder, and there remains until the balance again returns, when another impulse takes place, and so on in succession. Watches having the cylinder escapement were not known in France till the year 1728, when Julien le Roy obtained one of them from Graham.

+----------------------------------------------------------------------+ | [Illustration: Horizontal Escapement.] | +----------------------------------------------------------------------+

+----------------------------------------------------------------------+ | [Illustration: Duplex Escapement.] | +----------------------------------------------------------------------+

The _Duplex_ escapement is of a very peculiar construction, and nearly approaches the chronometer; it is probable that it was originally invented by Dr Hooke, although, as we now have it, it came from the hands of Tyrer. It is seen in our illustration. A, the escape-wheel; B, the escape-wheel teeth; C, the balance; D, the pallet of impulse; E, the ruby roller; F, a notch in ditto: 1, 2, 3, cogs or upright teeth on the rim of the escape-wheel. The balance is supposed to be turning downwards towards the right, the tooth of the escape-wheel just resting against the ruby roller. When this (which is called the return) vibration is complete, the balance, by the strength of the hair spring, is carried in the opposite direction, and as the notch F passes the tooth of the escape-wheel, this latter is enabled to pass the roller, and the upright tooth or cog falls upon the pallet D, and thus gives impulse to the balance. The next straight tooth of the escape-wheel is now resting against the roller _e_, and the same operation again takes place. This escapement is much superior to the horizontal, and is almost independent of oil. It can carry a balance of much greater weight, and when well made performs admirably. Duplex watches, however, should never be selected by persons who are accustomed to ride on horseback, as these instruments are liable to be affected by any sudden motion. Even the stepping quickly from a vehicle may stop them, and yet the escapement be as perfect as possible. They are only adapted for persons of very quiet habits. Thomas Mudge, in the year 1766, introduced an admirable invention, which, after many alterations and improvements, is now universally known as the '_Patent Detached Lever_' escapement, represented by--_a a_ the escapement-wheel, _b b_ the ruby pallets, _c_ the lever, _d_ the balance. On the axis of the balance _d_, towards the lever _c_, is a small disc of steel, into which is inserted a small pin made of ruby. This pin fits with great nicety into a notch or opening in the end of the lever _c_, upon which are firmly fixed the two pallets _b b_, into which are secured rubies very finely polished. The balance in its vibration on either side, carrying with it the steel disc and ruby pin, causes that pin to enter the notch in the lever and carry the lever with it, and at the same time, to draw the pallet from the tooth of the escapement-wheel _a_. Power being exerted upon this wheel by the mainspring, the wheel tooth gets disengaged from the locking-face of the pallet, forces itself down the slopes of the pallet, and thus gives impulse to the balance. At each vibration the same unlocking takes place, but as soon as the wheel tooth falls from the slope, the opposite pallet is prepared to receive the advancing tooth of the escapement-wheel, and so on in succession beat after beat takes place. So excellent was this escapement considered a few years back, that chronometers were made upon the principle, and placed in the Royal Observatory for public trial. But since then many improvements have been made in it, so that makers are now enabled to produce a pocket watch, with the short angle lever escapement, which marks time at a steady rate of within four or five seconds weekly,--a rate which approaches so near to the time-keeping of a pocket chronometer, that unless the minutest exactness for some specific purpose is required, the last-named watch is all that can be wished for.

+----------------------------------------------------------------------+ | [Illustration: Lever Escapement.] | | | | [Illustration: Chronometer Escapement.] | +----------------------------------------------------------------------+

About the year 1780 was invented the escapement which is now denominated the Detached or _Chronometer Escapement_ (see opposite page), the principles of which are the nearest approach to perfection, the impulse to the balance being given at the centre of vibration. A is the escape-wheel, B the escape-wheel teeth, C the roller let on the verge, or axis of the balance. This roller is a circle of polished steel, with a notch cut out of it, into one side of which, D, a flat polished piece of ruby is inserted for the acting part. Below this steel roller, carried on the same verge, is a smaller roller of steel (E), denominated the discharging pallet, having a sapphire fixed on its outer edge. F is a slender spring, which is screwed at I to the stouter one, having its fixture at the stud L, and polished away very thin at K, in order that it may bend readily, so as to cause very little resistance to the balance while forcing it on one side. G is a projecting piece, carrying an upright pin made of ruby, against which the wheel tooth B rests; at B is a small screw against which the spring L K G strikes, and thus prevents it from springing too far back. The action of these parts is as follows:--When at rest the circular edge of C is just clear of the two teeth of the wheel B, which cannot be set in motion while E and G remain quiescent; G rests against the screw at B, and the tooth resting against the locking pallet G, the escapement-wheel cannot turn. To set the chronometer going it is necessary to give it a rotary motion, which sets the balance in action. This causes the lower piece on the verge (called the lifting piece or discharging pallet) to strike against the end of the spring F, which, from its over-lapping the curved end of the prolonged spring K G, pushes it back, and thus releases the pin or locking stone G from before the tooth of the wheel: that is, it unlocks the escapement-wheel, which is immediately set in motion by the force of the mainspring. The same vibration given to balance and verge brings the ruby pallet D round before the tooth B, which strikes against it and carries it round. The recoil of the spring F has now brought the locking pallet G to catch the tooth B, the escapement-wheel is thus again stopped. But the stroke of the tooth upon the face of the ruby pallet D has driven the balance on in its vibration till it is counteracted by the tension of the balance spring, which brings it back again; in this return vibration the lifting pallet E, by its curved back, pushes the slender spring F before it, and passes it without affecting K, G, which is stiff enough to remain unmoved by F, even when this strikes and rests against it in recoiling. The wheel, therefore, continues locked on the upright pallet G, and the vibration proceeds uncontrolled till the great pallet is again brought round, and the balance spring again checks the vibration, the above process being repeated. In this escapement, consequently, part of one vibration in one direction, and the whole of that in the other, is performed without the balance being in any way under the influence of the motive power; while the parts are so contrived that the impulse given by the tooth of the escape-wheel, affects in a very slight degree the natural motion of the balance. It can be easily understood that the lifting pallet E can pass the spring F in one direction without moving K and G, while in the other it carries E and G with it.

+----------------------------------------------------------------------+ | [Illustration: Compensation Balance.] | +----------------------------------------------------------------------+

Several appliances have been from time to time introduced to correct the error in time-keeping caused by variations in the temperature, but none have come into such general use as that known by the term '_Compensation Balance_,' invented by Thomas Earnshaw, of London, and for which he received a government reward. This balance, when properly adjusted, causes the watch to keep the same time whether the temperature be 32 deg. or 90 deg.; while without it a watch will show a considerable difference in time, on being merely transferred from the pocket to the dressing-table, where, probably, the temperature would not be so high. Our woodcut represents a balance of this kind; the divided rim A A, is composed of steel and brass run together by fusion, the more expansible metal, brass, being placed outwards, the result of which is as follows:--Heat elongates the pendulum spring, and thereby causes a slower vibration of the balance. The same amount of heat will also expand the metals composing the balance; but as the inner rim of steel does not expand so freely as the outer one of brass, the conflicting action of the two tends to draw the free end of the circular rim inwards towards its centre, and thus decreases in all but one direction the diameter of the balance. This decrease tends to _quicken_ its vibration, and thus counteracts the effect of the elongation of the pendulum spring. In cold temperatures the pendulum spring is contracted, making the vibrations quicker, but the contraction of the brass rim draws the free end outwards, thus increasing its diameter, retarding its vibrations, and counteracting the effect of the contraction of the pendulum spring.

Many contrivances have been introduced to test the equality of compensation balances, but the majority have been abandoned from the circumstance that the heat was not equally distributed to the watches under trial. In pursuance of this object, an oven was invented, heated by hot water, which answers the desired end. It is an apparatus made of copper, two feet high, thirteen inches broad, and eight inches deep. From the top to the bottom, at the distance of fifteen inches, it is divided into two compartments. All around the upper one (except the front, which has a glass door through which the chronometers and watches are seen without opening it) is one inch of water. It has a chamber thirteen inches high, eleven inches broad, and seven inches deep for the reception of chronometers and watches. The water is introduced at the top in the same manner as a solar lamp is supplied with oil. The bottom compartment contains a jet of gas, which can at pleasure be regulated so as to keep the watch at any required temperature. The heat radiated from the inner surface of the chronometer chamber is thus equally distributed among the instruments under trial. A thermometer placed within the upper chamber indicates the temperature, and by this simple apparatus a watch can be regulated with the greatest nicety to suit the particular climate into which it may be taken.

The DIAL AND HANDS should be sufficiently in contrast one to the other to show the time at a glance. Dials are sometimes made of gold or silver, but these are not so distinctly seen as white enamelled dials, with black figures or numerals, and dark blue steel hands; the enamelled faces, although, perhaps, more brittle than gold or silver dials, are therefore in greatest request. Up to a comparatively recent date the seconds' hand was placed upon the level face of the watch, but sunk seconds are now everywhere in use, even in the cheaper sorts of watches. The chief objection taken to the sunk seconds is that it disfigures the dial by breaking the uniformity of the numeral letters, the VI being of course obliterated to make room for it, but this obliteration seems of smaller consequence than the confusion which may arise from the use of longer seconds' hands and their being at any time mistaken for that of the hour or minute.

The JEWELLING of a watch is an important part of its manufacture, inasmuch as it is by means of jewels that durability is chiefly secured. Watch pivots would rapidly wear out the metal in those parts in which there is continual friction, and jewelling has therefore become general. The watch-maker uses for his best watches a peculiarly hard kind of ruby, which has been known to withstand the wear and tear of the best part of a century without showing symptoms of yielding, whereas inferior jewels are perhaps scarcely so hard as the best tempered metal.

The FRAME, usually of brass gilt, sustains both ends of each axis, and is now principally designed to fit a full-plate movement or a three-quarter-plate movement. The former is undoubtedly the more simple construction, but with considerable disadvantage in taking to pieces the watch and putting it together again when repairs are needed. The examination of the escapement in a full-plate watch, and the cleaning, or altering, or oiling which may be needed, cannot be done without taking the whole movement to pieces. The three-quarter-plate movement is not only preferable on account of its superiority in respect to solidity, and the economy of labour in its manufacture, but from its being flatter than the full-plate watch, and allowing of repairs being more easily made.

The WATCH-CASE, which used to be of various materials, such as tortoiseshell, pinchbeck, or one of the precious metals, is now almost universally of gold or silver. Silver cases are invariably of the standard required by the law and stamped accordingly; gold cases vary in fineness,--some being made and stamped of 9 carat gold, but the best for wear, and as such preferred by the best makers, are of 18 carats, and are stamped as such with the hall mark, usually in three or four places,--on the bow, the pendant, and the inside of the case. Much depends upon the care with which this part of a watch is finished, for an ill-fitting case admits dust which renders frequent cleaning necessary, and prevents accurate time-keeping. After the casemaker has constructed the case it has to pass through several hands before it is completed,--for instance, it is one man's work to fit the works to the case by making the joint at the 12 o'clock and the bolt at 6 o'clock, and to supply the wheels to propel the hands; it is another's to perform the part of engine turner, and to mark the case with those curiously intricate lines whose wonderful precision cannot be secured by mere hand-work, but by a combination of mechanical and human labour; another's to finish the joints, or, as the uninitiate would perhaps call them, the hinges; and last of all the fitter of the case with springs, and polisher to give the necessary finish. In the same way has each part of the mechanism of the interior passed through a series of workmen's hands. Nearly every wheel and pinion has been separately made by men whose entire time is given to the perfecting of their several branches of labour, the subdivisions of which and their ramifications would need many lengthy chapters of description, to do them justice. The escapement is of itself a distinct department requiring a number of co-operating hands, from those which first shape the metal to the balance-maker working in brass, steel, or gold, and the final adjustment of the escapement-maker. The chain, the spring, the jewelling, the brass-work, the engraving, the gilding, have each their separate history, some of them being brought from one district and some from another, to be put together in the watch manufactory, which is finally to produce them unitedly as an entire watch. Division of labour provides a larger amount of skilled work, and a more satisfactory result, than any other method. The workman whose entire life is spent in making the head of a pin or in fixing it on, will do his work better than the man, however clever he may be, who should attempt to make the whole pin; and not only is the work thus better done, but it is done by combination much more expeditiously and cheaply. All that the watch-manufacturer can do by way of choosing his materials is, however, of course, but antecedent to his own work of actual construction, of finishing, examining, and regulating. He is to the watch what the architect is to a house; the latter is none the less the rearer of the structure because he did not himself make the bricks, or saw the timber, or mix the mortar. Each subordinate brings certain materials to the hand of the constructor, and he combines them, and gives them their places, he turns them into shape and produces them as a perfect whole. So the watch-manufacturer, instead of going himself back through the various stages of work which in Nuremberg-egg time had, perhaps, all to be done by one pair of hands, chooses, adapts, combines the labours of hundreds of busy collaborateurs, all of whom have made portions and pieces,--he alone makes the Watch.

COMPLICATED WATCHES are so called because besides the ordinary watch movement they possess other mechanism more or less complicated, by means of which they can indicate special portions of time,--as for instance the _Chronograph_, which marks on its dial the fifth of a second; the _Quarter_, and _Half-Quarter_, and _Minute Repeaters_, which furnish the time in the dark to within a minute, and are invaluable to invalids and blind persons; the _Clock-Watch_, which strikes the hours even in the pocket; the _Clock-Watch Repeater_, which strikes and repeats; the _Independent split Centre Seconds, and Fifth Seconds Watch_, which shows (by comparing the one with the other) the lapse of time to the fifth of a second; the _Perpetual Calendar Watch_, which shows the day of the week and of the month, the name of the month, the phases of the moon, &c.; the _Perpetual Calendar Repeating Watch_, which in addition to the calendar shows by a repeater the hour, quarter, and minute; and the _Meridian Watch_, which shows the time of day in any given number of places in any part of the world. A few words descriptive of the peculiarities of each of the above complicated watches will be necessary here, and observing the sequence as above, the following brief particulars will perhaps be sufficient for ordinary reference, or for being kept in memory.

+----------------------------------------------------------------------+ | [Illustration: Complicated Watches.] | +----------------------------------------------------------------------+