Thomas, professor of history at The Virginia Military Institute, has told the Diesel story thoroughly and with understanding. In his student days, Diesel became excited by the idea of developing an engine with high thermal efficiency, ideally a perfect Carnot cycle. The ideal had to be toned down in the long process of working out the theory of the engine, and still more when it came to constructing a practical mechanism, but the goal of high thermal efficiency was nevertheless achieved. This was not easy, and some of the difficulties that cropped were clearly of the inventor's own making.
The author suggests that Diesel was manic-depressive. He had a volatile temperament and the seemingly endless succession of problems that he kept encountering could well explain his frequent periods of depression.
He was without doubt a brilliant scientist and engineer, but he was evidently a poor businessman. He became very rich ...
