ELEMENTS. 269 



To speak of "parts" of light and heat, in 

 any sense of the word, is, therefore, to speak 

 that which has no meaning, even if we consider 

 those parts as the mere results of mechanical di- 

 vision. To speak of the half, or the quarter, or 

 any other fraction of light, is absurd ; and one of 

 those absurdities which, having crept into com- 

 mon language, tends to confuse our understand- 

 ing of things, even in their very simplest ele- 

 ments. 



Air, water, and solid matter, we can conceive 

 of as divisible into parts, mechanically, or into 

 pieces in all their various forms ; and chemically, 

 into their constituent parts or elements, in all 

 kinds of matter except those which we consider 

 them, and we consider them simple, just because 

 we have not been able to divide them chemically. 



Our means and methods of decomposition have 

 been much improved since the time when fire, and 

 air, and water, and solid matter under the ge- 

 neral name of earth, were considered as the four 

 elements of all created things. And, as we find, 

 in every case of decomposition, that the consti- 

 tuent, or elementary parts, have all different 

 qualities; and that the compound has qualities of 

 which we could have had no knowledge or even 

 suspicion, if we had known the elements only in 

 their separate states, we are enabled to say to 

 what the properties which we observe in different 

 kinds of matter are owing. But, as every new 

 combination is attended with new properties, we 

 have strong grounds for believing that every pro- 

 perty of matter, and every change in the appear- 

 ance of any portion of matter, is the result of 

 combination : that the property which we find 

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