Ross Precision Computer Instruction Manual

This deteriorating 16-page booklet was received with 1996.3077.01. It was copyrighted in 1919, but the address "340 Sansome St." is handwritten on page 3. Since the Computer Manufacturing Company of San Francisco did not move to this location until 1921, the instrument and manual were probably sent out in 1921 or later.
The manual contains general instructions, instructions for using the dial alone, instructions for separately using the linear slide rule attached to the instrument, hints for speed and accuracy, fundamental examples, technical details for calculating with logarithms and exponents, and practical applications from payroll to cube roots. Stamped on pages 8–9 is the text: ANOTHER HINT FOR SPEED (/) In locating answer coil, when a (/) check is desired, set slide ROUGHLY. Pages 9–16 are accessed by folding out the pages from the binding.
Currently not on view
Object Name
date made
Computer Manufacturing Company
Physical Description
paper (overall material)
overall: .2 cm x 12.5 cm x 20 cm; 3/32 in x 4 29/32 in x 7 7/8 in
place made
United States: California, San Francisco
ID Number
nonaccession number
catalog number
Science & Mathematics
Rule, Calculating
Slide Rules
See more items in
Medicine and Science: Mathematics
Slide Rules
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of B.K. Lunde, in memory of Roy Kegerreis
Additional Media

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