Model (scale 1:10) of the mechanism of Murray's engine

This shows the mechanism adopted in the self-contained engine, patented in 1802 by Matthew Murray of Leeds (see inv. 1897-127), for converting reciprocating motion of the piston into rotary motion of the output shaft. It is an application of the fact, originally published in 1666 by De la Hire, that when a circle rolls within another of double its diameter, any point in the circumference of the rolling circle describes a straight line.