Sinclair Cambridge pocket calculator, 1973.

Sinclair Cambridge electronic calculator, 1973.

Phillips's binary scale calculating machine, 1936.

Monroe's 'Full Automatic' calculating machine, 1922.

Printing blocks from a Japanese typewriter, c 1930.

Calculating wheels on Babbage's Difference Engine No 1, 19th century.

Alpina mechanical calculator, German, 1961.

HL-20 space taxi, 1991.

HL-20 space taxi, 1991.

Demonstration model of Babbage's Difference Engine No 1, 19th century.

Demonstration model of Babbage's Difference Engine No 1, 19th century.

Demonstration model of Babbage's Difference Engine No 1, 19th century.