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matter, but yet far removed from actual proof in its assumed 

 extension to the forces of organic life. To make this clear, we 

 must remember, that energy in its scientific sense represents work 

 done by a force operating during some period, and the doctrine 

 of its conservation may be briefly stated in the formula " the 

 sum of energy in the universe, whatever its transformation 

 may be, is a constant quantity," or in other words "no fresh 

 energy is bom into nature or dies out of it." This energy is 

 not the "force" of older philosophers, but requires for its 

 development vehicles of matter and ether. In its nature it is 

 classed as either Kinetic by virtue of its motion, or potential by 

 virtue of its position. If I wind up a clock causing the mass 

 of the weights to move through a given space, the work I do 

 is said to be equal to the change of Kinetic energy of the 

 weights; while the weights wound up and left at rest are said 

 to possess potential energy, because from their position, if let 

 free, they can restore the Kinetic energy or work expended in 

 raising them. Now accepting this dual hypothesis of Kinetic and 

 Potential energy, it is contended that all the forms which energy 

 assumes in the universe may be placed under one or other of 

 these classes, and that all the operations of natm'e, both organic 

 and inorganic, are confined to the change of energy from one 

 kind to another ; motion, heat, molecular separation, chemical 

 separation, radiant energy, elecricity, or magnetism and life. 

 Even admitting that the universe consists of matter and ether, 

 acting upon and with each other, the form- and essence of these 

 are an inscrutable secret, and however interchangeable some 

 results and operations may appear, it is a long step to the 

 assumption that the mechanism of nature was at one time set 

 a-going, and ev€r since continues to act without an active 

 superintending power, and receives no addition of energy; and 

 further that the original energy is not merely conserved, but is 

 able to act upon and develop organic life with its numerous 

 functions and its added power of thought and expression. 

 Moreover, the correlative idea suggested by Sir William Thom- 

 son, of the dissipation of energy seems to follow as a necessary 

 consequence fi'om this hypothesis, and hence it is by some writers 

 maintained that so far as this earth is concerned, all the energy 

 tends during its transformation to pass into heat, that this is 

 then in some degree dissipated through the surrounding ether, 



