Replica of original micrometer caliper by Jean Laurent Palmer, patented in France 7.9.1848, range 0 to 20 mm, made after 1867 by Brown & Sharpe
Replica of the original micrometer caliper by Jean Laurent Palmer, patented Sept 7th 1848. The original was exhibited at the Paris Exposition of 1867 and upon this 'Systeme Palmer' being seen by Joseph R. Brown and Lucien Sharpe, founders of Brown and Sharpe of Providence, Rhode Island, it immediately impressed them with its possibilities, particularly the manner of markings on the barrel and they bought one, bringing it back to the United States. They copied its general principle to make a sheet plate gauge for which they knew there was a demand. This was the origin of the modern hand held micrometer gauge. This instrument has a screw of 1 mm pitch, and the rotating thimble is divided into 20 parts so that a the user can measure objects up to 20 mm long in steps of 0.05 mm.