Counting machine designed by Bryan Donkin

Plan with front and end elevations, sections and detail entitled "An automatic counting machine for recording number of items produced" designed by Bryan Donkin.

Up until 1819 bank notes had been numbered by hand, a process which had become impracticable. Donkin’s new ‘counting machine’ counted the number of revolutions of any machine by means of a series of notched ratchet wheels and clicking levers. Donkin saw it as useful for measuring “the number of revolutions made by a mill wheel or of the strokes of a steam-engine beam in a given time, or the number of revolutions made by the wheel of a carriage or a perambulator over a certain space.”

Its simplicity, accuracy and effectiveness in counting and recording the revolutions of any machine to the tens of thousands earned it the nickname ‘tell-tale’.