Superseding Steam: The Napier and Rankine Hot-air Engine

This paper discusses an ‘improved’ form of hot-air engine designed and developed by two figures familiar to anyone concerned with engineering in Glasgow in the nineteenth century. The first, William John Macquorn Rankine, is perhaps best known as the author of a monumental series of academic engineering textbooks. The second is Rankine’s friend, the educated marine engineer and man of science, James Robert Napier. The paper is also intended as a contribution to the history of power — a topic ably treated elsewhere and, in one aspect, by Richard Hills in his excellent Power from Steam (1989). My discussion can also be interpreted as a contribution, perhaps more provocatively, to the history of ‘technological failure’. Indeed I have, elsewhere, taken the Napier and Rankine hot-air engine, amongst other machines using air as their working substance, as examples of precisely that: failure. In an earlier paper I considered technological failure and its ramifications broadly, but especially as categories used by, and only too familiar to, the nineteenth-century engineers themselves. Amongst these other machines were the hot-air engines developed by the aristocratic Sir George Cayley, better known for his (not unconnected) interest in aeronautics; the so-called ‘caloric’ engine of the ‘Yankee from Sweden’, John Ericsson; and the hot-air engine of the brothers Stirling. There were two such: the Reverend Robert Stirling, minister at Galston in Scotland; and James Stirling, Glasgow-trained engineer, working in the 1840s at Dundee. It is remarkable — but true — that at the time of their protracted ‘development’, all of these engines were given by contemporary commentators, alternately, the status both of failure and success. It rather depended whom you spoke to, or what you read. This was so much the case that it was difficult — perhaps impossible — for contemporaries to guess what the final outcome would be for these engines. This was particularly the case because of the ways in which the engines were discussed. Although all of the engineers paid lip service to science, none of them were averse to species of technological hype better suited to the scandal sheet than the scientific meeting room. These engineers and their promoters came across as obsessive, if not always adept, media managers: Cayley tried to use the name of his London friend Charles Babbage, notorious promoter of the difference and analytical engines, as a witness endorsing the success of own air engine; James Stirling allowed the Dundee newspapers, the Mechanics’ Magazine, and eventually a tougher forum — the Institution of Civil Engineers — to multiply and scrutinise his practical case for a hot-air engine patented in 1816, 1827 and again in 1840,