CHAPTER I. 



ENERGY IN GENERAL. 



Origin of the Idea of Energy. - The Phenomena of Nature bring 

 into play only two Elements, Matter and Energy. — § i. 

 Matter. — § 2. Energy.— § 3. Mechanical Energy. — § 4. 

 Thermal Energy.— § 5. Chemical Energy. — § 6. The Trans- 

 formations of Energy. — § 7. The Principles of Energetics. — 

 The Principle of the Conservation of Energy. — § 8. Carnot's 

 Principle. — The Degradation of Energy. 



Origin of the Idea of Energy. — A new term, namely 

 energy ^\vdA been for some years introduced into natural 

 science, and has ever since assumed a more and more 

 important place. It is owing to the English physicists, 

 and especially to the English electrical engineers, that 

 this expression has made its way into technology, an 

 expression which is part and parcel of both languages, 

 and which has the same meaning in both. The idea 

 it expresses is, in fact, of infinite value in industrial 

 applications, and that is why its use has gradually 

 spread and become generalized. But it is not merely 

 a practical idea. It is above all a theoretical idea of 

 capital importance to pure theory. It has become 

 the point of departure of a science, energetics, which, 

 although born but yesterday, already claims to 

 embrace, co-ordinate, and blend within itself all the 

 other sciences of physical and living nature, which the 

 imperfection of our knowledge alone had hitherto 

 kept distinct and apart. 



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