Category: Sphygmograph
Estimated Date: 1875
Name: Sphygmograph, Richardsons
Manufacturer: Allan and Hanbury

Description: 5×3×2” leatherette case contains device similar to Dudgeons but with 2” rod which extends and has an adjustable weight to adjust pressure rather than screw spring. The body of the instrument is 2” long, there is a 2’ sq. clockwork mechanism to turn the smoked paper on a rod drive. Marked #294 in base.

Reference 1: 122