For recording the arrival time of racing pigeons, developed originally in the 19th century by W. H. Turner. The birds are taken to the point of departure and released at a given time, their homing instinct compelling them to return to their home loft as rapidly as possible. On arrival the identification ring each pigeon carries is detached and placed in a small thimble for insertion into a slot in the pigeon clock, and a lever is pressed which causes the time of insertion to be recorded on a paper tape. The rings are stored in a container in the order in which they are inserted into the clock. Various devices are fitted to prevent tampering and the clocks aare sealed. After the race the records are removed to determine the exact time of arrival of the birds. Early pigeon clocks were made in Britain, others in Belgium where the sport is also popular.