The circular slide rule developed around 1920 by Jules Arnault and Louis Paineau comes in a wooden frame, to give it durability and ease of use; but it is so pretty you can – and I did – hang it on your wall!

Arnault-Paineau slide rule

Aside from being pretty, this is an ingeniously designed and very well-made calculator. You can find all the details in this new article on my History-of–Computing site.

Enjoy!