Automatic calculator: Chambon's "Multiplicateur Enfantin" length 6 3/8 inch
Introduced in 1876, this is a simple multiplication aid. On a paper sheet, which is wound between two cylinders, the numbers 2 to 50 are written at the heads of columns. The columns contain the multiplication table of the top number, as far as times 28, and the products appear alongside the multipliers which can be seen on the centre strip.
The left-hand opening is used if the number to be multiplied is under 26 and the right hand opening for numbers between 26 and 50.