KINDS OF STATIC CONDITIONS. 437 



and take no real part in producing the effect. Conditions, 

 like causes, may also be classed in a more scientific manner, 

 according to the various sciences to which they belong, 

 and which will probably be their classification when know- 

 ledge has sufficiently advanced ; thus we may have condi- 

 tions of time and space, mathematical and geometrical 

 conditions of the masses, molecules, and atoms, static and 

 dynamic mechanical conditions of the same, thermic, optic, 

 electric, magnetic, chemical, vital, psychical conditions, 

 &c., of them ; and all the subdivisions of these. 



A real condition is one which is indispensable to the 

 production of the effect in the particular instance ; it is 

 often more fundamental and comprehensive than the 

 corresponding apparent one, because it agrees with the 

 exceptional cases, whilst the apparent one does not. An 

 apparent condition is one which appears to agree with all 

 the phenomena, but which, on deeper or more extensive 

 examination, fails generally or in certain cases ; thus 

 Ampere's theory that magnetism is due to innumerable 

 electric currents continually flowing in one uniform direc- 

 tion round the molecules of the iron, agrees admirably 

 with all the phenomena of electro-magnetic attraction, 

 repulsion, and motion, but is defective, because there is 

 no known instance of electric currents being maintained 

 without a continual consumption of power and evolution 

 of heat ; but in magnets there is no such source of power, 

 and no evolution of heat. An essential condition is one 

 without which the effect cannot be produced even in the 

 smallest degree. 



A releasing or exciting condition is one which enables 

 a latent force to become free, and excites it to operate ; 

 it takes only an apparent and not any real part in pro- 

 ducing the effect due to the liberated force. Its action 

 is essentially distinct : for instance, friction excites and 



