reported that Sir Humphry Davy had "discovered that 

 the application of a certain gas, 1 5 times heavier than 

 the atmosphere, to the mechanism of the steam 

 engine, will produce a power fully equal to that which 

 now results from the application of steam." ^^ This 

 gas (mercury ?) was not to be the successor to steam, 

 however. 



A water-ether binary vapor cycle, often discussed, 

 was made to do useful work by at least one builder. 

 Steam, exhausted from a conventional steam engine, 

 was condensed in a tubular heat exchanger, contain- 

 ing ether, that served as an ether boiler. The ether 

 was then expanded in a separate working cylinder 

 and condensed in a conventional surface condenser. 

 Such a power plant was actually used about this time in 

 a vessel plying the Mediterranean between Marseilles 

 and Algiers. ^^ 



Dozens of internal combustion engines, in which 

 the energy of fuel was imparted directly to the 

 working medium, had been designed and tested 

 since the time of Christiaan Huygens, who in 1680 

 tried to use gunpowder in a vertical engine cylinder. 

 In the 1820's, Samuel Brown built in England a 

 number of atmospheric gas engines in which an 

 intermittent gas flame in the working cylinder 

 heated air for each stroke of the engine. Instead of 

 making use of the expansive force of the heated air, 

 the designer arranged for the air to be cooled, and the 

 vacuum thus produced enabled the atmosphere to 

 do work on the outside face of the piston. Samuel 

 Morey, in America, adapted the idea to a turpentine 

 engine and added a carbureting chamber to evaporate 

 and collect the combustible turpentine vapor. But 

 the internal combustion engine in any form was not 

 in general use by midcentury. 



Heated air had been more successfully employed by 

 compressing a charge of air in a compressor cylinder, 

 heating the charge in a furnace, and delivering it 

 under pressure to a working cylinder. James Glaze- 

 brook, an English engineer, when designing an air 

 engine in 1797, noted the advantage of using the air 

 exhausted from the working cylinder to assist the 

 furnace in heating the next charge of air.^* This 

 was the idea of the regenerator, which in Captain 



Ericsson's caloric engine was to be referred to as the 

 "grand principle." Robert and James Stirling, of 

 Scotland, patented air engines in 1827 and 1840,^' and 

 for three years one of their engines supplied power 

 for a foundry in Dundee.^* A regenerator had been 

 considered by the Stirlings as a necessary unit in each 

 of their designs, and the 1 840 improvement consisted 

 of a separate "plate box," or regenerator, an im- 

 perfect version of the one finally adopted by Captain 

 Ericsson. 



Nor was Captain Ericsson a latecomer among air- 

 engine designers. In 1826, in England, he had built 

 an air engine with a separate vessel for heating the 

 air, and a "refrigerator" for cooling it; while this 

 engine would run, it could not be lubricated satis- 

 factorily because of high air temperatures. It had 

 no regenerator.^^ In 1833 Ericsson patented his first 

 "caloric" engine (fig. 8), which had a regenerator 

 in the form of a tubular heat exchanger.^* In the 

 ensuing discussion of the merits of the caloric idea 

 as advanced by Ericsson, the celebrated Professor 

 Faraday devoted one of his popular lectures to 

 Ericsson's engine. The inventor probably was in 

 the audience when the professor, at the outset of his 

 lecture, declared that it had just occurred to him 

 that the explanation that he had carefully prepared 

 of the engine's principle was in error, and that at the 

 moment he did not know why the engine worked at 

 all.^'^* 



A host of other ideas for prime movers had been 

 brought forward in the decades before 1850. Like 

 the caloric engine, many of the engines would run 

 and would do useful work; but of all the schemes for 

 supplanting steam engines with superior prime 

 movers, none had yet been able to show an economic 

 advantage over conventional steam systems. It was 

 on this shoal that many a promising device was 

 grounded. The question of "Will it pay?" was one 

 that had to be convincingly answered in the affirma- 

 tive before an engine could be sold to a critical buyer. 

 Let us look for a moment, then, at the actual per- 

 formance of the caloric engines of the Ericsson. 



22 Mechanics' Magazine, London, 1824, vol. 1, p. 68. 



^Practical Mechanics Journal, London, 1853—1854, vol. 6, p. 

 217; W. J. M. Rankine, A Manual of the Steam Engine, ed. 15, 

 London, 1902, p. 444. 



24 British Patent 2164, August 3, 1797. 



25 British Patents 5456, July 20, 1827, and 8652, October 1, 

 1840. 



2' Minutes oj Proceedings of Institution of Civil Engineers, London, 

 1853, vol. 12, p. 600. 



iT Ibid., p. 351. 



28 British Patent 6409, April 4, 1833. 



2" Mechanics' Magazine, London, March 1, 1834, vol. 20, p. 

 368. 



48 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



