Slide rules are a major area of interest for serious collectors of
scientific & mathematical calculators. Here is a necessary addition to
any collection of slide rules.

Here is a major compendium of nearly all slide rule patents issued
worldwide: over 1000 PDF files present full, printable images of over
900 patents, searchable on any computer by patent number, date of
issue, & inventor's name. In addition, US patents are arranged by
patent class.

In addition, over 200 of the patents on this CD are of foreign origin.

Also included are selected patents on portable nomographic, linear &
chart calculators, as well as other calculators relying on opposable
logarithmic scale technology. Graphical calculators for trigonometric
calculations are also included.


Jack