EXPLANATION OF LAWS. 551 



corrode or blacken organic compounds. This is a 

 case of causation, but of remote causation ; and is 

 said to be explained when it is shown that there is an 

 intermediate link, namely, the separation of some of 

 the chemical elements of the organic structure from 

 the rest, and their entering into combination with the 

 acid. The acid causes this separation of the elements, 

 and the separation of the elements causes the disorga- 

 nization, and often the charring of the structure. So, 

 again, chlorine extracts colouring matters (whence its 

 efficacy in bleaching), and purifies the air from infec- 

 tion. This law is resolved into the two following 

 laws. Chlorine has a powerful affinity for bases of all 

 kinds, particularly metallic bases and hydrogen. 

 Such bases are essential elements of colouring mat- 

 ters and contagious compounds : which substances, 

 therefore, are decomposed and destroyed by chlo- 

 rine. 



4. It is of importance to remark, that when a 

 sequence of phenomena is thus resolved into other 

 laws, they are always laws more general than itself. 

 The law that A is followed by C, is less general than 

 either of the laws which connect B with C and A 

 with B. This will appear from very simple con- 

 siderations. 



All laws of causation are liable to be counteracted, 

 or frustrated, by the non-fulfilment of some negative 

 condition : the tendency, therefore, of B to 'produce 

 C may be defeated. Now the law that A produces B, 

 is equally fulfilled whether B is followed by C or not ; 

 but the law that A produces C by means of B, is of 

 course only fulfilled when B is really followed by C, 

 and is therefore less general than the law that A 

 produces B. It is also less general than the law that 



