Merchants' Graphic Profit Finder, mid 20th century

1950-1970

Arithmetical medal and numerical pocket piece

1753

Slide rule for interest calculations

1824

McFarlane calculating cylinder, c.1835.

circa 1835

'Supra Bareme', ready reckoner, c 1925.

circa 1925

Two gilt bronze arithmetical medals, c.1753

1750-1755

One of Two gilt bronze arithmetical medals, c.1753

1750-1755

One ot two gilt bronze arithmetical medals, c.1753

1750-1755