POWERHOUSE COLLECTION

Notes

It appears from the engraved names that GD Kittoe designed the indicator. He had worked over many years for both Isambard Brunel, designer of the Great Eastern, and William Froude, a distinguished scientist in the area of fluid mechanics. Kittoe assisted Froude with the design and construction of a towing tank at Torquay, Devon, for studying the resistance offered to model ship hulls when towed through water. (The Froude number, analogous to the Mach number for aircraft, is named in honour of this research, which aimed to discover the most efficient hull shape.) In November 1875 Froude wrote of Kittoe that he was an "admirable craftsman and sketcher and a thorough mechanic". (David Brown "The way of a ship in the midst of the sea: the life and work of William Froude" p 149) David Brown mentions that James Rorison installed a 'dynamometer' that had been designed for the Great Eastern's paddle engines by William Froude and Henry Brunel (son of Isambard) and made by GD Kittoe ("The way of a ship in the midst of the sea: the life and work of William Froude" p 92). This is probably a reference to the indicator, so it is possible that Kittoe was not the sole designer, but the evidence of maker on the device itself is stronger than the written account. Brown also states that Rorison was delighted with the device. In 1867 Kittoe entered into partnership with Peter Brotherhood to make engines, at 53-56 Compton Street, Clerkenwell, London. The indicator shows that Kittoe must have been in business at 56 Compton Street by 1863. After Kittoe retired in 1871, Brotherhood moved the business to Peterborough; the company still exists there and now designs and manufactures steam turbines with power outputs between 1MW and 40 MW. The indicator was made by James Munro in London in 1863. According to Mari Williams ("The precision makers: a history of the instruments industry in Britain and France, 1870-1939" p 20), a James Munro was apprenticed to an instrument maker in 1783, his family followed this trade and had premises in Lambeth, and one of his grandsons, RW Munro, dissolved his partnership with his brother in 1864, set up in business on his own and became a renowned maker of precision instruments. Gibson Street, where the indicator was made, is in Lambeth, and the James who made this indicator could well have been the brother of RW Munro. This indicator is similar in design to the earliest indicators made by Scotsman John McNaught, in that the indicator cylinder and spring are concentric with the recorder drum. McNaught is usually credited as the first to use a rotating drum to replace the oscillating tablet of the Watt/Southern indicator; it has also been suggested that this idea first occurred to Henry Maudslay or his partner Joshua Field. The McNaught indicator introduced a torsion spring which returned the recording drum to its starting position at the end of the inward stroke of the engine piston. McNaught later offset the recorder drum from the indicator piston axis in order to provide greater flexibility to change the pressure sensitivity of the indicator. Perhaps for the task of monitoring the huge engines on the Great Eastern it was thought that the simplicity and robustness of the early type of indicator was preferable.