INTERMIXTURE OF EFFECTS. 517 



to a still greater heat, it became mercury again, and gave 

 off a gas which did support life and flame. Thus the 

 agents which by their combination produced red pre- 

 cipitate, namely the mercury and the gas, reappear as 

 effects resulting from that precipitate when acted upon 

 by heat. So, if we decompose water by means of iron 

 filings, we produce two effects, rust and hydrogen: now 

 rust is already known by experiments upon the com- 

 ponent substances, to be an effect of the union of iron 

 and oxygen : the iron we ourselves supplied, but the 

 oxygen must have been produced from the water. 

 The result therefore is that the water has disappeared, 

 and hydrogen and oxygen have appeared in its stead : 

 or in other words, the original laws of these gaseous 

 agents, which had been suspended by the superinduc- 

 tion of the new laws called the properties of water, 

 have again started into existence, and the causes of 

 water are found among its effects. 



Where two phenomena, between the laws or pro- 

 perties of which considered in themselves no con- 

 nexion can be traced, are thus reciprocally cause and 

 effect, each capable in its turn of being produced from 

 the other, and each, when it produces the other, ceasing 

 itself to exist (as water is produced from oxygen and 

 hydrogen, and oxygen and hydrogen are re -produced 

 from water) ; this causation of the two phenomena by 

 one another, each of them being generated by the 

 other's destruction, is properly transformation. The 

 idea of chemical composition is an idea of transforma- 

 tion, but of a transformation which is incomplete ; 

 since we consider the oxygen and hydrogen to be pre- 

 sent in the water as oxygen and hydrogen, and capable 

 of being discovered in it if our senses were sufficiently 

 keen : a supposition (for it is no more) grounded solely 

 upon the fact, that the weight of the water is the sum 



