ABSTRACT
Boiler-making was entrusted to the blacksmith, but became a separate though ancillary trade in the Midlands about 1790. Boulton and Watt got their boilers from Thomas Horton of West Bromwich and from John Wilkinson of Bradley and Bersham. To increase the heating surface—practically the only essential of a boiler at that time—relative to the water content, the next step was to elongate the boiler, retaining the same cross-section, and to supply it with flat or rounded ends, thus arriving at the waggon boiler. The waggon boiler has been frequently attributed to him, but the evidence is all to the contrary; boiler design was one of the matters to which he did not devote much attention. The first kind of boiler that Evans describes is similar to what was known in England as the egg-ended boiler—a simple cylinder with hemispherical ends, externally fired.
