Definitions for "TOURBILLON"
A device invented to eliminate errors of rate in the vertical position. It consists of a mobile carriage or cage carrying all parts of the escapement, with the balance in the center. The escape pinion turns around a fixed fourth wheel. The case makes one revolution per minute, annulling errors of rate in the vertical position.
A complication designed to eliminate or substantially reduce positional timing errors due to the effects of gravity or unbalanced friction. The invention consists of mounting the entire escapement on a platform or mobile carriage which rotates on its axis within a given time period. Since any positional errors are reproduced at regular intervals, they tend to cancel eachother out.
A device in a mechanical watch that eliminates timekeeping errors cause by the slight difference in the rates at which a watch runs in the horizontal and vertical positions. The tourbillon consist of round carriage, or cage, holding the escapement and the balance. It rotates continously at the rate of once per minute.
Keywords:  unusual, declined, longer, sound, small
a small sound as it was no longer unusual to have declined
Keywords:  keeping, device, time
a device for keeping time