It was produced to demonstrate the principles of the transit of Venus, which took place on June 6 of that year.
The model is not to scale (astronomers at the time hoped to use the Venus transit to gain an accurate measurement of the Earth’s distance from the Sun), but it does show the essential relationships between Earth, Venus and the Sun for the period of the transit.
Turning the handle causes Venus to pass across the face of the sun, while Earth rotates about its axis. The slanting line inscribed around Earth indicates the southern limit of potential observation sites, while the clock face below shows the transit duration.
Cole & Son conducted their business between 1751 and 1766 from a building adjoining a popular drinking establishment.
The pamphlet to the right advertises ‘Mathematical and Optical Instruments of all Sorts Accurately made according to the Best & Latest Improvements By Benjamin Cole at the Orrery next the Globe Tavern in Fleet Street London’.