When the 18th-century English instrument maker Thomas Wright catalogued the collection to which this set of brass plates belongs, he was evidently at a loss as to their function. They clearly did not belong to the contemporary instrument-making repertoire and Wright could suggest only that they bore some relation to gunnery. A more plausible explanation is that they were used to display the disposition of troops.
There are five full-length and four half-length plates, with the shorter pieces marked 'Grenadiers' and numbered from 1 to 4. Four of the longer plates each represent a 'Division' and are numbered in sequence from the first to the fourth, each subdivided into three further sections. All also have 'Angle' marked at one end of the plate in such a way that they are most readily assembled into a square. The final plate, with a table of numbers, perhaps displays an arrangement of these or similar plates.
The plates are stored in a simple wooden case.
Dimensions (full-length plates): 113 x 18 mm
Orrery Collection (Christ Church)
Inventory no. 50,368