The great obstacle to close rate in a modestly priced watch is the balance wheel. This wheel requires careful adjustment for temperature error and for poise. Of these two disturbing factors poise is the most annoying to the owner because lack of it makes the watch a very erratic timekeeper. A watch in which the parts are not poised is subject to a different rate for every position it is placed in. This position error, as it is called, can and often does cause a most erratic and unpredictable rate. Abraham-Louis Breguet, the celebrated Swiss-French horologist of Paris is credited with the invention, in 1801,[1] of his tourbillon, a clever way to circumvent this error. [Illustration: Figure 1.--BREGUET'S TOURBILLON. At C is shown the carriage which revolves with pinion B carrying the escapement and balance around the stationary wheel G. (After G. A. Baillie, _Watches, their history, decoration, and mechanism_, London, Methuen, n.d.)] His solution was to mount the escapement in a frame or "chariot" which revolved, usually once a minute, so that with each revolution all possible positions were passed through (fig. 1). This gave the watch an average rate which was constant except for variations within the period of revolution of the chariot. Only a very skillful workman could, however, work with the delicacy necessary to produce such a mechanism. The result was that few were made and these were so expensive that it continued to be more practical to poise the parts in a conventional movement. The idea of revolving the entire train of a watch, including the escapement, seems to have evolved surprisingly slowly from Breguet's basic invention of the revolving escapement. In constructing a watch wherein the entire train revolves, no such delicate or precise workmanship is required as in the tourbillon. Due to the longer train of gears involved the period of revolution is much slower. Position errors average out as certainly if not as frequently. In Bonniksen's "Karrusel" watch of 1893[2] the duration of a cycle is 52.5 minutes[3] while in the Auburndale Rotary which we are about to discuss the period of each revolution is 2-1/2 hours. ----- [1] Paul M. Chamberlain, _It's about time_, New York, 1947, p. 362. [2] British patent 21421, granted January 21, 1893. [3] Chamberlain, _op. cit._ (footnote 1), pp. 229, 230. The Invention