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 correcter 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 the behaviour of steam in the 

 arose a rather angry controversy I cylinder at all calculable were so 

 which has been summed up in the far wide of the mark, that a 

 question, ' Is it water or iron ? ' ; general consensus seems to prevail 

 I do not know that this controversy among theoretical engineers that 

 has been as yet completely decided." progress depends less upon an 

 See also Peabody, ' Thermo- immediate application of thermo- 

 dynamics of the Steam - Engine,' dynamic principles, than upon a 

 4th ed., New York, 1900, p. 301 careful analysis guided by theory 

 sqq. of elaborate tests upon the 

 1 This explains how it comes various types of engines now in 

 about that theoretical thermo- use. Such experiments are ac- 

 dynamics is still regarded with cordingly following the example 

 suspicion, not to say aversion, by of Hirn being carried out in 

 many engineers of the old school, many scientific establishments in 

 whose knowledge is principally this country, on the Continent 

 based upon experience derived from of Europe, and notably in the 

 the steam-engine. The first theo- United States of America, and are 

 retical treatment of the steam- i elaborately recorded in many 

 engine by Rankine in England, : modern publications. See Pea- 

 and Zeuner in Germany, exhib- ; body, ' Thermo - dynamics of the 

 ited such enormous discrepancies [ Steam - engine,' 4th ed., preface, 

 between theory and practice ; ' and chaps, xiii. and xiv. ; Ewing, 

 the simplifying assumptions which ' The Steam-Engine,' 1894, p. 31. 

 were introduced in order to make 



