The present watch is part of a small series of high precision timekeepers made by S. Smith & Son. It was submitted for trial at the Kew Observatory where it obtained a Class A Certificate with 73.4 marks. Its movement was most probably supplied by Bahne Bonniksen and then finished and adjusted by Smith & Son.
The Karussel or Carrousel was patented in 1882 by the Danish watchmaker Bahne Bonniksen who had immigrated to England.
Both Karussel and Tourbillon are revolving escapements with the escapement placed on a small rotating platform, a device to eliminate errors of rate in the vertical positions. The Karussel escapement however is driven by a fourth wheel, which is not fixed but rotates within the platform. Consequently it is turning at a much slower rate than tourbillon carriages, varying from 34 to 52.5 minutes per full rotation depending upon the design. It is also more robust and easier to produce than a tourbillon, hence less expensive.