252 THE FOKCE8 OF mOKGANIC NATURE. 



there must be still further effects corresponding to this re- 

 gaining cause : the total effect of c would thus be > e, which 

 would be contrary to the supposition c=e. Accordingly, 

 since c becomes e, and e becomes/, &c., we must regard these 

 various magnitudes as different forms under which one and 

 the same object makes its appearance. This capability of 

 assuming various forms is the second essential property of all 

 causes. Taking both properties together, we may say, causes 

 are (quantitatively) indestructible and (qualitatively) convert- 

 ible objects. 



Two classes of causes occur in nature, which, so far as 

 experience goes, never pass one into another. The first class 

 consists of such causes as possess the properties of weight 

 and impenetrability ; these are kinds of Matter : the other 

 class is made up of causes which are wanting in the proper- 

 ties just mentioned, namely Forces, called also Impondera- 

 bles, from the negative property that has been indicated. 

 Forces are therefore indestructible , convertible, imponderable 

 objects. 



We will in the first instance take matter, to afford us an 

 example of causes and effects. Explosive gas, H-f-O, and 

 water, HO, are related to each other as cause and effect, 

 therefore H +O =HO. But if H + O becomes HO, heat, cal, 

 makes its appearance as well as water ; this heat must like- 

 wise have a cause, x, and we have therefore H+O+^=HO 

 + caZ. It might, however, be asked whether H-f O is really 

 =HO, and os=:caZ., and not perhaps H+O = ca?., and 03=HO, 

 whence the above equation could equally be deduced ; and so 

 in many other cases. The phlogistic chemists recognized the 

 equation between cal. and &, or Phlogiston as they called it, 

 and in so doing made a great step in advance ; but they in- 

 "volved themselves again in a system of mistakes by putting x 

 in place of O ; thus, for instance, they obtained H=HO+oj. 



Chemistry, whose problem it is to set forth in equations 

 the causal connection existing between the different kinds of 



