the ternary
calculating machine
of Thomas Fowler

About the site

This site is owned and maintained by Mark Glusker. I work as a Principal Engineer for Novartis in San Carlos, California, developing new medical devices.

The mechanical calculating machines displayed on this site are all from my private collection, gathered from various sources over the past ten years. To try to keep a limit on the size of the collection, I have focused on fully automatic calculators commercially available during the 1960's, and where possible, only the top-of-the-line models from each manufacturer.

The other half of the site features the model I designed and built of Thomas Fowler’s ternary calculating machine. This is a project that owes its existence to Pamela Vass and David Hogan, of Devon, England. I am grateful to them for the opportunity to help recreate a unique calculating machine that had been lost to the world for over 150 years.

Copyright Notice

All text and pictures on and its subdirectories are copyright 1999 – 2005 Mark Glusker unless otherwise noted. Images and limited portions of text may be used for non-commercial purposes if credited as follows:

“Mark Glusker”

Please contact Mark Glusker for permission to use text and images for commercial purposes.

Site history:

29 January 2005
first version of the new site published

28 May 2005
added Marchant Tenkeymatic and Olivetti Logos 27-2
added video of Fowler machine to the "About the machine" pages

26 November 2005
added Friden SBT and Victor 79-88-54 and Victor 10-871
added placeholder page for Other Calculating Devices


calculating machines
of the 1960's

all images copyright Mark Glusker 1999 to 2005 - all rights reserved