RECENT IMPROVEMENTS IN WATCH MAKING.—The Waltham Watch Co. in troduced a novel improvement in the movements of their make a few years ago, which has helped to offset any damage done to the train following the breaking of the mainspring. The center pinion is removably fixed to the center staff ; the pinion has its axial hole screw-threaded to correspond with a similar thread upon the staff, the direction of thread being such that the strain of the mainspring.
acting through the teeth of the barrel upon the pinion, will force it against a shoulder formed for the purpose on the staff, making it practically a single piece ; lint should the mainspring break, the violent recoil of the broken spring would simply serve to unscrew the pinion from the staff without harm to either. instead of having the effect of breaking the teeth of the barrel and pinion.
The Son-Mllynetie Watch.—The Wal tham Watch Co. has recently perfected and put on the market the non-magnetic watch, the result of expensive experi ments since 18ST ; such watches being especially valuable to electricians and other persons liable to go near dynamos, electric car motors, and the like. This achievement in modern horology has been accomplished by substituting for steel as used in the balance, roller, hairspring, and pallet and fork (which together constitute that portion of the watch designated as escapement), metals or alloys which are non-magnetic, and which yet possess the properties of elasticity and expansion to such relative proportion as to en able them to compensate for the varying conditions of heat and cold.
How difficult a problem this has been to solve may be imagined when it is considered that no single known metal possesses all the qualities required. And. further, that each of the different portions of the escapement requires to be constructed of metal having certain characteristics which shall fit it for the peculiar duty of that part, and which may not be demanded by some other part.
There are, however, two requisite properties common to all the parts : First, sufficient ductility to be capable of being brought into the required form ; second. non-susceptibility
to magnetic influence. The function of the fork demands a metal able to withstand wear ; the hairspring must possess elasticity in a high degree, and yet must be capable of being fixed or "set" in proper spiral form.
The duties of the balance require that its body be made capable of a certain degree of expansion under the influence of heat, but it must not be too expansive; while the outer lamina of the rim must have a very high ratio of expansion, without undue rigidity.
CLocKs.—Recent Improventents.—blocks have recently been combined with dating stamps, for use in banks and in city and court offices of record, by which the letters and papers filed are not only marked with the day, month, and year. but the hour and minute of the day the papers were filed.
Outside of the automatic novelties known as the swing clock and the jumper clock, the improvements in clocks have been limited to various different constructions of the parts. Among these various improvements may be mentioned the Blakesley clock, which employs in lieu of the usual pallet a worm engaging with the escape wheel, the worm shaft having an arm so connected with the pendulum as to impart a rotary movement thereto.
The late Henry J. Davies, so long connected with the Ansonia Clock Co., made many improvements in that particular class of goods put on the market by the Ansonia Co.. among which may be mentioned a construction in which the main wheel of the clock has attached to it the inner end of the mainspring, which is arranged in concentric relation with the center arbor of the clock. The clock case has a loose back or back piece, having attached to it a rigid ratchet adapted to rotate freely around the main wheel arbor when winding up the clock, and having one or more clicks to prevent the back motion of the mainspring. The main arbor also was tubular, and through this extended the minute wheel arbor, having a key at its end for the adjustment of the hands from the rear of the clock.