Interestingly John Napier invented many other aids to calculation. Perhaps the most famous of these are his bones. When laid out in the correct manner they can be used as a set of multiplication tables.
This is a set of fruitwood Napier's Bones, England, dated 1717, with broad cubes and square rod, and ten four-sided multiplier rods, on rectangular tabulat with fixed multiplier rod and support rod, in fruitwood slip case with stamped date and fleurs-de-lis and incised geometric decoration to both sides, (lacking cover), wd. 3 3/4 in.Made by the Webber family, colonial Boston cabinet makers and handed down by descent. Came to auction 2001. Photos reproduced here with permission of David Baum.