"It has been proved," wrote Mr. Wilder, "that 

 explosions in steam engines are the consequence of 

 the escape of elementary caloric . . . ." This caloric, 

 he went on, is an "imponderable fluid of incalculable 

 velocity which will shatter to pieces everything that 

 offers resistance to its progress in a certain direction." 

 Editor Munn agreed with Mr. Wilder except in one 

 detail: "We differ from Mr. Wilder in our opinion 

 regarding what his caloric is. We believe it to be 

 electricity." 



The idea that caloric was an indestructible fluid was 

 supported by a general belief that a given quantity of 

 heat, used to generate steam for a steam engine, passed 

 through the engine without any diminution in 

 quantity. Carnot, in his 1824 treatise, made this 

 assumption, although his notes indicate that he was 

 not satisfied with this aspect of the caloric theory.^^ 



Mechanics' Magazine,^ of London, in 1852 explained 

 why "the production of mechanical force by heat is 

 unaccompanied by any loss of heat." The amount of 

 heat contained in a given quantity of steam could be 

 determined by condensing the steam in a water bath 

 and noting the rise of temperature of the water. If 

 the same quantity of steam were conducted to the 

 water bath through a steam engine cylinder, the 

 engine would produce useful work, and it would be 

 found that the "same elevation of temperature will 

 take place as when the steam was not previously em- 

 ployed" in the engine. 



Captain Ericsson was not concerned with describing 

 caloric, however. He intended to use it — over and 

 over again. 



Although Ericsson fostered the popular idea that 

 the caloric was trapped in the interstices of the wire 

 mesh — numbering some 50,000,000 "minute cells" =' — 

 and was to be given back to the next charge of air 

 passing through the regenerator, a calculation shows 

 that no such fanciful explanation is needed. The 

 total volume of the iron in the wire mesh was nearly 

 5)^ cubic feet. 5* When the regenerator reached 

 equilibrium conditions, there would be a gradient of 

 temperature from the cold end of the regenerator to 

 the hot end. The cold end was probably about 120° 



F., while the hot end may have been close to the 

 operating temperature of the working cylinder, about 

 480° F. Taking into account the specific heats of 

 air and iron, it can be shown that any element of the 

 regenerator would be heated and cooled by successive 

 charges of air through a range of not more than 

 fifteen degrees. Thus, the regenerator was of ample 

 size to act as a heat exchanger, but a regenerator, un- 

 fortunately, could not, even under the influence of 

 Captain Ericsson's sanguinity, seize caloric after it 

 had done work and return it to the engine to be used 

 over again. 



The regenerative principle is widely used today 

 in power plants. In gas turbine power plants, a 

 heat exchanger is employed to heat air on its way 

 from the compressor to the combustion chamber. 

 The exhaust air from the turbine is the heating 

 medium. In steam power plants, steam is bled 

 off from the turbine at as many as eight different 

 stages, to be used for heating feed water in shell-and- 

 tube type heat exchangers. The purpose of the re- 

 generator is to reduce irreversible heating of the 

 working medium; that is, to use a source of heat 

 only slightly above the temperature of the medium 

 being heated. Several engineers in Captain Erics- 

 son's time recognized that the regenerator could 

 utilize heat that would otherwise be wasted, but 

 not heat that already had done work. 



Other contemporaries of Ericsson were not troubled 

 by any such niceties. Professor Harvefeldt, of 

 Sweden, who may have been the one who planted 

 the seed of the caloric engine, was quoted as having 

 said in a lecture, attended by the young John 

 Ericsson, that "there is nothing in the theory of heat 

 which proves that a common spirit-lamp may not 

 be suflficient to drive an engine of a hundred horse- 

 power." ^^ 



John O. Sargent, confidant and solicitor for Captain 

 Ericsson, had said in 1844 at a public lecture in 

 Boston that "Ericsson's theory of heat is altogether in 

 opposition to the received notion, that the mechanical 

 force produced will bear a direct known proportion 

 to the caloric generated . . . ." ^' 



In the same vein, the editor of Appletons' Mechanics' 

 Magazine and Engineers' Journal wrote: °^ 



53 Carnot, op. cit. (footnote 19). 

 " Vol. 56, p. 449. 



^' Mew-Tork Daily Times, January 12, 1853. Also, see 

 footnote 57. 



^' See footnote 4. No calculation of volume was made in 

 1853. 



5' Applelons' Mechanics' Magazine and Engineers' Journal, 1852, 

 vol. 2, p. 261. 



=8 Ibid. 



™ Applelons' Mechanics' Magazine and Engineers' Journal, 1853, 

 vol. 3, p. 117. 



PAPER 20 : JOHN ERICSSON AND THE AGE OF CALORIC 



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