28 Wilde, Evolution of the Mental Faculties. 



absolute motion at the same time, the quantity of "rest" 

 or "potential" of the endothermic body is annihilated 

 simultaneously with the creation of motion and energy in 

 the same body. In fine, the dogma that the quantity of 

 rest and motion in the universe is at all times the same 

 is one of those platitudes which, under the pretence of 

 knowledge, evoked the ridicule of Locke * and is equiva- 

 lent to affirming that what a Cartesian knows, and that 

 which he does not know, constitute the sum of all the 

 knowledge in the universe, and that the sum-total of all 

 the knowledge and of all the ignorance in the universe 

 is a constant quantity. It will be evident that similar 

 trifling equations may be multiplied indefinitely. 



Just as the Cartesian principle of the conservation of 

 molar motion fails entirely when applied universally, so 

 also does the same principle fail in its universal application 

 to the molecular motions of bodies, as I have already 

 shown in my paper read before the Society in i896.f 



Although I have demonstrated the attribute of 

 spontaneous motion and energy in endothermic bodies, 

 the principle may also be well illustrated (i) by the heat 

 generated through the explosion of gaseous mixtures and 

 by other chemical reactions ; (2) by discharges from 

 statically electrified bodies and the Leyden jar ; (3) the 

 evolution of dynamic electricity from an electro-magnet 

 after contact with the exciting machine is broken ; 

 (4) the generation of electricity from primary and 

 secondary batteries ; (5) the mechanical energies and 

 motions generated by springs and by the free action 

 of gravity.;): 



* Locke, Human Understanding, Chap. VIII., of lyijling Propositions. 



t Manchester J\fc?noirs, Vol. XL., pp. 61-71. 



J The difficulties and contradictions involved in applying the principle 

 of conservation to the gravitating force have been stated at length by Faraday 

 in a lecture dealing exclusively with the question. Froc. Roy. Institution, 



1857. 



