The Circle of Proportions and the Horizontal Instrument

This section contains a printable replica of Oughtred's Circles of Proportion and his Horizontal Instrument.

The replica is based on the beautiful example by Robert Davenport, now held at the National Museum of Scotland, here

Recently, I learned about a new website that has the most information about the instrument anywhere, at the University of Lisbon  here.    I  very much recommend that you have a look at this site.  It's simply amazing.     

Link to the  Circles of Proportion pages

Link to the Horizontal Instrument Pages