Arithmetical Jewel, 1619.

Arithmetical Jewel, 1619.
The 'Arithmetical Jewel' publicised by William Pratt in 1619. This instrument combines features of an abacus with those of pen reckoning. Numbers are put in by moving the flags to reveal dots. Sums are then worked out with a pen and paper.
 
Currently on display in:
Mathematics
Year made :
c.1619
Inventory number :
1952-206