This object is part of a collection relating to the history and development of calculating devices assembled by Assoc Professor Allan Bromley of Sydney University, comprising mathematical instruments, slide-rules, mechanical and electronic calculators, electronic analogue computers, computer components, kit computers, education computers, and associated ephemera.

Allan Bromley was a lecturer and researcher at the University of Sydney Basser Department of Computer Science from 1978 until his untimely death in August 2002. He specialised in Computer Architecture, Computer Logic and in particular the History of Computing. He was regarded as the world authority on Charles Babbage's Calculating Engines (instigating the building of the Difference Engine No.2 at the Science Museum London) and the Antikythera Mechanism and had extensive knowledge of calculators, analogue computers, logic, stereopsis, totalisators, clocks and time keeping and mechanical engineering.

Bell Punch Company Ltd, c 1936

The Bell Punch company did not manufacture any calculators until the 1930s when in 1936 the parent company, Control Systems, acquired the rights to the adding machines of the Comptometer type manufactured by Petters, Limited, of Yeovil, England and sold under the name Pettometer".

Mechanical direct key desktop calculator with cover, Sumlock adding machine Model 912, metal / plastic, made by Bell Punch Company Ltd, England, c. 1936

Sterling calculator in green hammertone without ha'penny and farthing keys.

Made: 1931 - 1941

SUMLOCK

2010/1/247

1931 - 1941

145 mm

325 mm