Marie-Antoinette's Watch: Adultery, Larceny & Perpetual Motion

Chapter 9

Friction was only one of several issues confronting watchmakers. Others included the effects of gravity, the fragility of these increasingly intricate timepieces, and the tendency of watches to expand as their mechanical innards became more complex.

One of Breguet's masters, Jean-Antoine Lépine, made one of the great leaps forward in reducing watch size. He had originally been a master at enamel-work, and as an enamelist, he knew that bulbous watches in rounded cases were almost impossible to cover in colored glass. What he needed was a flat, large watch onto which he might place his designs and drawings.

His great innovation was the Lépine caliber, the piano key caliber that reduced the main plate in a movement to little more than a few crossed pieces of metal. Over the years, watches had become thicker and thicker, with some watches approaching two centimeters from front to back. Lépine, after experimenting with different gearing systems, eventually created his caliber, a flat, disconnected series of small metal plates or bridges that simply held the gears in place. The difference in movements was striking. Prior to Lépine's invention, watch movements looked like thick sandwiches of metal held together with little pillars of brass or iron - in short, they looked like miniaturized mantle clocks. Lépine's first improved bridge looked like that same sandwich stripped of its filling - the gears and the springs - and spread out on a plate. The rearrangement allowed watches to be thinner and offered "economical advantages, and removal of the fusee also eliminated an important source of friction."66

Gravity, too, continued to bedevil watchmakers. With a clock's pendulum, the arc of motion was constant. However, watches used spring a with a balance wheel, which served the same regulating function by "swinging" quickly back and forth. Gravity, especially when compounded by the haphazard position of a timepiece bouncing around in an aristocrat's pocket, could distort the wheel's equilibrium, causing the watch to run slow or fast.

Gravity in the form of a watch hitting a hard marble floor could also put an end to a nicely ticking Breguet or Lépine caliber. Inadvertent shocks could cause the crystal covering the watch face to break, and parts to become misaligned. Wind and rain could get into non-watertight cases, wreaking havoc on the delicate mechanisms within.

Thanks to wine-soaked evenings, and because the king enjoyed hunting, many elegant Parisians' watches ended up falling to the ground or, more harmfully, onto the hard marble floors of Versailles. Breguet saw the effects first hand. When the Comptesse de Provence, the king's sister-in-law, dropped her watch, breaking both the dial and the crystal face, it was to Breguet that she, like many of her peers, sent the watch to be repaired. To address the problem of fragility, in 1790 Breguet developed an antishock mechanism, a taut spring that held the escapement and balance wheel in place. Because it hung in space, he called it the para-chute. When a watch with a para-chute dropped, the springs took the brunt of the force. Breguet's ability to shockproof watches became so renowned that, on one occasion, Talleyrand, a powerful French diplomat under Louis XVI, asked him to give a demonstration. Breguet threw a watch to the ground and lifted it again, showing that it was still running. Talleyrand was surprised and delighted, commenting that Breguet was really practicing wizardry and not watchmaking.

The strength of his watches was also demonstrated by the straight-laced yet curious British General Sir Thomas Makdougall Brisbane, a governor of New South Wales and science buff, who, "possessing one of these chronometers, subjected it to great trials by constantly wearing it on horseback; and during several long voyages, in sixteen months the greatest variation was only a second and a half."67