1851 Great Exhibition: Official Catalogue: Class V.: Perceval Parsons
From Graces Guide
642. PARSONS, PERCEVAL M., C.E., 6 Duke Street, Adelphi — Patentee and Designer.
Patent switches adapted to the ordinary double T rail. Single patent switch, adapted to Barlow's patent broad flange rail.
Patent crossing for railways, adapted to the ordinary double T rail.
Normanville's patent axle-box. The lower chamber of the axle-box, which contains the journal and bearing, is cast in one piece, and closed by means of an apparatus fitted to it, for the purpose of excluding grit or dirt, and preventing the waste of grease.
Patent machine for dressing mill-stones, with a millstone to illustrate its action. With the aid of this machine, it is stated that a boy can dress a pair of stones in less time and with greater ease than a millwright.