Cottam & hallen surveyor c 1830
A very rare cottam & hallen surveyor, c 1830. Probably this instrument used in the construction of railways in united kingdom. They have in 1839 patent pending on a railwaywheel. The brass arch contains the following inscription: inches fall in 3 feet – 36 till 0 till 36 measures distribution -inches rise in 3 feet. On both end of the mahogany shelf is an eyepiece and shoot cross present. The inscription is cottam & hallen, 2 winsley str london. Length 140 cm.