it remained in use for nearly 70 years, and has been preserved by the Science Museum in London. Although termed 'semi-portable', as they could be transported and installed without being dismantled, these engines were essentially stationary. They were used to drive such barn machinery as pumps and hammer mills, bone-crushers, chaff and turnip cutters, and fixed and mobile threshing drums.

It was not until about 1839 that the truly portable engine appeared, allowing the application of steam