ENERGY AND ITS TRANSFORMATIONS. 



7 



elaboration of the most wonderful and mysterious of 

 organisms. It is only in the structures which are their 

 work that the strange, the incomprehensible phenom- 

 ena of life are exhibited to the intelligence which 

 vainly endeavors to understand them.* 



3. Energy, living Force," ever-living force, as we 

 are now learning to regard it ; vis viva, as its first 

 discoverer, Leibnitz, called it ; the force illustrated in 

 all life and motion, as we now know it ; energy, as Dr. 

 Young first denominated it : all these expressions for 

 one common quality of every body, substance, or 

 system, in motion either as to its atoms or molecules 

 or as to its mass, denote that mysterious property 

 by which all growth, all life, all changes in physical 

 things or physical substance are brought about and 

 continued. The work of the vegetable kingdom, in 

 the elevation of the simpler, inorganic compositions 

 found in nature to the higher, complex, organic forms 

 in which they find their culmination ; those of the ani- 

 mal system which take these complex forms and erect 

 them in a still more complicated animal structure and 

 supply it with the powers of animal hfe ; the work of 

 the living creature in again reducing these complicated 

 structures to the lower and simplest forms, availing it- 

 self of their latent energy in the production of all the 

 grandest results of physical and intellectual life : all 

 these are but manifestations in various ways of the 

 ever-living forces, the never-ceasing energies, of the 

 universe. 



In its two forms, kinetic and potential, actual and 



*The preceding matter is from the vice-president's address before 

 the American Association for the Advancement of Science, R. H. 

 Thurston, 1878. 



