136 



SCIENTIFIC THOUGHT. 



and waste (degradation) of energy, have hardly resulted 

 in those practical achievements and improvements l which 

 in other departments of applied science, notably in 

 chemistry and electricity, have followed upon new dis- 

 coveries, the influence of these new conceptions on 

 scientific thought and method themselves has been 

 enormous. Next to the conceptions introduced by 

 Darwin into the descriptive sciences, no scientific ideas 

 have reacted so powerfully on general thought as the 

 ideas of energy. A new vocabulary had to be created ; 

 the older text-books, even where they dealt with known 

 subjects in perfectly correct ways, had to be rewritten ; 

 well-known and approved theories had to be revised and 

 restated in corrector terms, and problems which had 

 lain dormant for ages to be attacked by newly in- 

 vented methods. I propose in the rest of this chapter 



greatly shaken. . . . There thus 

 arose a rather angry controversy 

 which has been summed up in the 

 question, ' Is it water or iron ? ' 

 I do not know that this controversy 

 has been as yet completely decided." 

 See also Peabody, ' Thermo- 

 dynamics of the Steam - Engine,' 

 4th ed., New York, 1900, p. 301 

 sqq. 



1 This explains how it comes 

 about that theoretical thermo- 

 dynamics is still regarded with 

 suspicion, not to say aversion, by 

 many engineers of the old school, 

 whose knowledge is principally 

 based upon experience derived from 

 the steam-engine. The first theo- 

 retical treatment of the steam- 

 engine by Rankine in England, 

 and Zeuner in Germany, exhib- 

 ited such enormous discrepancies 

 between theory and practice ; 

 the simplifying assumptions which 

 were introduced in order to make 



the behaviour of steam in the 

 cylinder at all calculable were so 

 far wide of the mark, that a 

 general consensus seems to prevail 

 among theoretical engineers that 

 progress depends less upon an 

 immediate application of thermo- 

 dynamic principles, than upon a 

 careful analysis guided by theory 

 of elaborate tests upon the 

 various types of engines now in 

 use. Such experiments are ac- 

 cordingly following the example 

 of Hirn being carried out in 

 many scientific establishments in 

 this country, on the Continent 

 of Europe, and notably in the 

 United States of America, and are 

 elaborately recorded in many 

 modern publications. See Pea- 

 body, ' Thermo - dynamics of the 

 Steam - engine,' 4th ed., preface, 

 and chaps, xiii. and xiv. ; Ewing, 

 'The Steam-Engine, ' 1894, p. 31. 



