[Form letters (2) to chairmen and directors of railway companies re his improved turntable] / Thos. Pearson. [Pearson, of Hall Carr Terrace, Sheffield, had improved the turntable originated by Isaac Dodds in 1839. The first letter bears testimonials by directors of the Sheffield and Rotherham Railway Co., and a draft ms. letter (2p.), 1842 Sept 2, to G. M. Miller (then engineer of the London and Greenwich Railway)/Thos. Pearson, re his turntable. With lithographed drawing (plan and section) of the turntable, and an ms. copy (4p.) of an advertisement for same from the Railway Times of 14 Jan 1843]