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Engineers and Millwrights 56 and 53 Compton Street, Clerkenwell, London. 
1872 Invented a new type of engine with three cylinders at 120 degrees, the forerunner of the radial engine.
1873 Showed the new engine at the Vienna Exhibition. The balance of the new engine made it well suited to driving torpedoes and for powering fans. This led to uses in electricity generation, air compressors and high speed engines.
1874 Produced a simple steam steering gear, which was applied to the twin-rudder Channel steamer 'Castania'. It utilised Brotherhood's well-known three cylinder radial engine 
1878 Supplied Brotherhood's patent steam steering gear
1878 Partnership dissolved. '... the Partnership heretofore subsisting between us the undersigned, Peter Brotherhood and George Gatton Melhuish Hardingham, as Mechanical Engineers, Millwrights, and Ironfounders, at Compton-street, Clerkenwell, Middlesex, under the style or firm of Brotherhood and Hardingham. has been dissolved as from the 31st day of December, 1877; and that the said business will, in future, be carried on by the said Peter Brotherhood alone...'