Edmund Beckett and Henry Hardinge Cunynghame

“ The Swiss watches have almost universally the horizontal escapement. It is found that—for some reason which is apparently unknown, as the rule certainly does not hold in cases seemingly analogous—a steel scape-wheel acts better in this escapement than a brass one, although in some other cases steel upon steel, or even upon a ruby, very soon throws off a film of rust, unless they are kept well oiled, while brass and steel, or stone, will act with scarcely any oil at all, and in some cases with none. ”

“ A modern watch consists of a case and framework containing the four essential parts of every timepiece, namely, a mainspring and apparatus for winding it up, a train of wheels with hands and a face, an escapement and a balance-wheel and hair-spring. ”

“ Each portion of the rim of the balance is composed of an inner bar of steel with an outer one of brass soldered, or rather melted, upon it, and carrying the weights b, b, which are screwed to it. As the temperature increases, the brass expanding must bend the steel inwards, and so carries the weights farther in, and diminishes the moment of inertia of the balance, the decrease of rate being inversely as the diameter of the balance-wheel. ”

“ The "going-barrel," which is fitted to most modern watches, contains no fusee, but the spring is delicately made to diminish in size from one end to the other, and it is wound up for only a few turns, so that the force derived from it does not vary very substantially. The unevenness of drive is in modern watches sought to be counteracted by the construction of the escapement and balance-wheel. ”

“ In the usual and simplest form there is a centre seconds hand which normally remains at rest, but which, when the winding handle is pressed in, is linked on to the train of the watch and begins to count seconds, usually by fifths. A second pressure arrests its path, enabling the time to be taken since the start. A third pressure almost instantaneously brings the seconds hand back to zero, this result being effected by means of a heart-shaped cam which, when a lever presses on it instantaneously, flies round to zero position. ”

“ The pallets in a lever escapement (except bad and cheap ones) are always jewelled, and the scape-wheel is of brass. The staff of the lever also has jewelled pivot-holes in expensive watches, and the scape-wheel has in all good ones. The holes for the balance-pivots are now always jewelled. The scape-wheel in this and most of the watch escapements generally beats five times in a second, in large chronometers four times; and the wheel next to the scape-wheel carries the seconds-hand. ”

“ The prejudice against machine-made watches has been very strong in England, but is dying out—not, unfortunately, before much of the trade has been lost. A flourishing watch industry exists in Switzerland in the neighbourhood of Neuchatel. A watch in a stamped steel case can now be made for about five shillings. There is no reason why in such a neighbourhood as Birmingham the English watch industry should not revive. ”

“ Calendar work on watches is, of course, fatal to great accuracy of time-keeping, and is very complicated. A watch is made to record days of the week and month, and to take account of leap years usually by the aid of star-wheels with suitable pauls and stops. The type of this mechanism is to be found in the calendar motion of an ordinary grandfather's clock. ”

“ The reason why this friction cannot be avoided with a pendulum is that its arc of vibration is so small that the requisite depth of intersection cannot be got between the two circles described by the end S of the lever and any pin in the pendulum which would work into it; whereas, in a watch, the pin P, which is set in a cylinder on the verge of the balance, does not generally slip out of the nick in the end of the lever until the balance has got 15° past its middle position. ”

“ It may be said briefly that every part, including the toothed wheels, is stamped out of metal. The stamped pieces are then finished by cutters and with milling machinery. Each machine as a rule only does one operation, so that a factory will contain many hundreds of different sorts of machines. The modern watchmaker therefore is not so much of a craftsman as an engineer. The effect of making all the parts of a watch by machinery is that each is interchangeable, so that one part will fit any watch. ”

“ It is usual to time the watch's going when the mainspring is partly wound up, as well as when it is fully wound up, and then by removing parts of the hair-spring to get such an adjustment that the rate is not influenced by the lesser or greater extent to which the watch has been wound. ”

“ The cases of modern watches are made sometimes of steel, artificially blackened, sometimes of compounds of aluminium and copper, known as aluminium gold. Silver is at present being less employed than formerly. The hair-springs are often of palladium in order to render the watch non-magnetizable. An ordinary watch, if the wearer goes near a dynamo, will probably become magnetized and quite useless for time-keeping. ”

“ During the 18th century a series of escapements were invented to replace the old crown wheel, ending in the chronometer escapement, and though great improvements in detail have since been made, yet the watch, even as it is to-day, may be called an 18th-century invention. ”

“ The position of the lever with reference to the pallets is immaterial in principle, and is only a question of convenience in the arrangement; but it is generally such as we have given it. The principle is the same as in the dead-beat clock escapement, with the advantage that there is no friction on the dead faces of the pallets beyond what is necessary for locking. ”

“ This was to diminish the inertia of the balance-wheel in proportion to the increase of temperature, by means of the unequal expansion of the metals composing the rim.
Invention in watches was greatly stimulated by the need of a good timepiece for finding longitudes at sea, and many successive rewards were offered by the government for watches which would keep accurate time and yet be able to bear the rocking motion of a ship. ”

“ Hence a tool is not allowed to make more than a given quantity of parts without being examined and readjusted, and from time to time the pieces being put out are tested with callipers. The parts thus made are put in groups and sorted into boxes, which are then given over to the watch-adjusters, who put the parts together and make the watch go. The work of adjustment for common watches is a simple matter. ”

“ The pallets are undercut a little, as it is called, i.e. the dead faces are so sloped as to give a little recoil the wrong way, or slightly to resist the unlocking, because otherwise there would be a risk that a shake of the watch
Fig. 4. would let a tooth escape while the pin is disengaged from the lever. There is also a further provision added for safety. In the cylinder which carries the impulse pin P there is a notch just in front of P, into which the other pin S on the lever fits as they pass ”

“ The average daily departure from the mean daily rate, that is the average error due to irregular departures from the average going rate, must not exceed 2 seconds a day except where due to position, when it may amount to 5 seconds. ”

“ When the balance is turning in the direction marked by the arrow, and arrives at the position in which the dotted tooth b has its point against the triangular notch V, the tooth end slips into the notch, and, as the verge turns farther round, the tooth goes on with it till at last it escapes when the tooth has got into the position A ”

“ Harrison's compensation consisted of a compound bar of brass and steel soldered together, having one end fixed to the watch-frame and the other carrying two curb pins which embraced the spring. As the brass expands more than the steel, any increase of heat made the bar bend ”

“ Watches have also been made containing small musical boxes and arranged with performing figures on the dials. Repeaters are striking watches which can be made at will to strike the hours and either the quarters or the minutes, by pressing a handle which winds up a striking mechanism. ”