An Exactus adding machine

Before the days of digital devices and battery driven pocket calculators, there were mechanical adding machines, often small table top devices. At Market Lavington Museum, we have such a machine, formerly used by the Williams family of Easterton Manor Cottage.

We believe this one dates from about the 1950s and it was specifically designed for adding (and subtracting) pounds, shillings and pence (£ s d). It coped with hundreds of thousands of pounds, but also dealt with farthings. Those quarter of an old penny coins were minted until 1956 and went out of use in 1961.

Twisting the silver knob on the right, moved the flap to adjust the machine from adding to subtracting.

The machine was operated by by using a stylus to move slides inside each column of figures. When not in use, the stylus, which had a pen on its other end, was stored away in the hole at the top right of the machine.