Bahne Bonniksen, a Dane living in London, invented and patented the Karrusel in 1895 as an alternative to the tourbillon. Both are types of revolving escapement, but the Karrusel is less apt to get damaged if worked on by an unskilled watchmaker. Bonniksen calculated the train as for a classical watch. For a regular watch the beat would be 18,000 beats per hour. However, since the carriage rotates around the 4th wheel (planetary or epicyclic gearing) 8/7 times per hour, that is 8/420 times perinute, the number of beats will be smaller for this amount. So if the 4th wheel has 70 teeth, the actual number of teeth engaging the escape wheel in one minute is 70 (1-8/420). If the escape wheel has 15 teeth and its pinion 7 leaves, the watch beats [70(1-8/420)x15x2x60]/7 =17,657 and 1/7 times per hour (assuming that the center wheel has 80 teeth and the carriage wheel has 70 teeth). This train was designed by Bonniksen and used by many others.It seems that from the very beginning there was speculation as to why Bonniksen did it this way. Some suggested that he did not take into account the influence of the extra rotation, which is not present in the tourbillon because the 4th wheel is stationary. Others claimed that it was easier to manufacture the standard train than a new, atypical one. But in fact, in order to have the subsidiary seconds make one revolution per minute, he had no other choice than to manipulate the beat. If he wantd to have the correct subsidiary seconds he could not design any decent train beating 18,000. The best possible trian beating 18,000 would be: Center wheel 60 teeth 3rd wheel 64 teeth, pinion 8 leaves 4th wheel 61 teeth, pinion 8 leaves escape wheel 15 teeth, pinion 6 leaves carriage wheel 61 teeth. But this would be a poor design from a number of points of view, since the center wheel has fewer teeth than the third wheel, and in general a train with small number of teeth is not efficient.