22 M. C. Szily on the Deduction of the Second Proposition 



illustrated, by saying that if we put pcascods into the mathe- 

 matical mill we cannot expect it to yield wholesome wheat- 

 flour. Such ill-founded calculations do not advance, hut 

 retard truth ; they do so especially when applied to such ques- 

 tions as arc related to physical geology, upon which opinions 

 are adopted by large numbers who know nothing of mathema- 

 tics;, and by whom mathematical symbols are too commonly 

 taken as tests of truth, and upon whom their parade exercises 

 a sort of fascination like that said to affect birds under the 

 glance of the rattlesnake. Were this intended as a refutation 

 of the Rev. 0. Fisher's paper, and not merely to point out the 

 invalidity of his conclusions resting on such infirm data, I 

 might point to the physical impossibility which appears to mo 

 to be involved in the first part of the answer he has given to 

 his own question, page 317, "If the work of descent of the 

 crust is not transformed into the heat of volcanic energy, it 

 may be asked what becomes of it?" He says part of it "is 

 transformed into heat within the nucleus," his own assumption 

 being that the nucleus itself is hotter than the heat of vulca- 

 nicity. But this, as well as the string of improbable suppo- 

 sitions not containing any thing new, with which the author 

 endeavours to prop up old volcanic theories at the conclusion 

 of his paper, I pass without remark. 



IV. The Second Proposition of the Mechanical Theory of Heat 

 deduced from the First. By C. Szily, Budapest*. 



THERE is not, and never will be, any theory which could 

 dispense with fundamental hypotheses incapable of 

 demonstration and explanation ; still a theory must be regarded 

 as more perfect the less it stands in need of such undemon- 

 strable assumptions. The mechanical theory of heat, accord- 

 ing to the present view of it, rests upon two propositions of 

 this sort. The first (named after Mayer and Joule) is no 

 other than the universal principle of the Conservation of 

 Energy, in its application to heat. 



The second proposition (that of Carnot and Clausius) cannot 

 be expressed so simply, or be so readily fitted into the frame- 

 work of a general physical principle, as the first-mentioned. 

 This second proposition is formulated by Clausius as follows f : — 



" Whenever a quantity of heat is converted into work, and 

 the body through which the conversion is effected is finally 



* Communicated by the Author. Translated from the Mathcmatikcd 

 JErtekezesek, vol. iv. 1875. The original memoir was presented to the 

 Hungarian Academy of Sciences, May 10, 1875. 



t Pogg. Ann. 1854, vol. xciii. 



