Description

A fine example of the famous Farey ellipsograph by W. & S. Jones, London c.1820

Consisting of two concentric rotating and racked rings, racked bridge for the bow compass and adjustable double brass and steel bed, this instrument has encountered dampness in it’s 200 year life but the oxidation/pitting is minor. It retains most of it’s bright, golden lacquer and works smoothly. The bow compass fits in a triangular pivoting head of the bridge and was intended to be held in place by a thumb screw (threads a little worn). The bow compass has an adjustable head and inking pen with butterfly nut for drawing the ellipses. 

The 6 x 5 inch instrument is housed in it’s original mahogany case with one C-hook and good hinges. Inside the lid is the original price of the ellipsograph in Pound Sterling and American dollars. An export item, for certain. 

An original drawing of this very instrument (designed and patented by Farey) is seen in the last photo. The last original and signed Farey was sold for twice the asking price of this piece. A marvel of engineering with machining tolerances hard to match today. The double rack and pinion guides are in top condition (noting a slight wobble in the screw of one-could be tightened down) and the concentric rings rotate with the help of six (6) turned pegs. There is a linear scale (in inches) to indicate the foci of the ellipse. The outer adjustable brass bar (with two knurled nuts) is to square and secure the instrument against a drawing/architect’s table. A rare survivor by a top Firm.

John Farey  patented a perspective machine in 1807 and the ellipsograph/elliptograph in 1810.