92 RADIANT MATTER IS ABSORBED. 



at once. A ray of light, dispersed by the action of a prism, presents to us a spectrum in 

 which we see plainly intrinsic differences of the various parts. Exposed to this spec- 

 trum, or to these coloured spaces, vegetable juices of different tints undergo modifica- 

 tions ; some are changed by the blue, some by the yellow, some by the red ray. If we 

 examine the conditions under which these things take place, as we have done for heat 

 and for tithonicity, we find similar evidences of absorption. Thus, chlorophyl, which 

 gives a green colour to leaves, undergoes a change by light, and becomes white ; and 

 when, by prismatic analysis, we inquire what rays are active in producing this effect, we 

 find that they are those which have been absorbed. 



374. For plants, therefore, coloration is intimately connected with chemical action. 

 There is a chemical reason why leaves are green and flowers are never black, but un- 

 fold a painted corolla ; and, guided by these principles, we can see that all those various 

 active principles which are stored up, all the different juices which circulate, are con- 

 nected with, and have borne a certain relation to the coloured portions. In a rose, the 

 leaves of which are green, and petals red, and interior organs of reproduction of a gaudy 

 yellow, these tints do not result from a wanton play of Nature, but are rather evidences 

 of premeditation and forethought. As anatomists have been enabled to deduce from 

 their studies a testimony for the existence of a Universal Designer, so, too, might chem- 

 ists, from reasons on the colours of a wild flower, show that those colours are the means 

 of accomplishing certain ends. 



375. These things hold, whatever doctrines we assume respecting the nature of light; 

 whether, with NEWTON, we regard it as consisting of emanations of particles which are 

 exceedingly small, or, in the more refined views of modern philosophers, as undulations 

 of an elastic medium. The waves of sound which pass through our atmosphere in 

 like manner produce striking and permanent results, and even are often connected with 

 those higher philosophical events which not only belong to material things, but also to 

 the world of intellectuality. There are strains of music which have been listened to 

 in youth, and have communicated a permanent impression to the brain, which, in 

 after life, spontaneously present themselves to the memory. It is true that these things 

 originate in intellectual operations, but it is equally true that the channels of commu- 

 nication through which they have passed from mind to mind belong to the inorganic 

 world. It is atmospheric pulsations which are thus registered in the brain. In that 

 wonderful organ they are stored up, and amid the hourly change of every part of the 

 living system, the constant introduction of new particles, the passing away of those 

 which are dying or effete, these aerial pictures are permanently preserved. In an in- 

 stant, and spontaneously, there flashes across the memory a recollection of events which 

 transpired half a century before, and which have been buried in oblivion. So, also, 

 with the undulations of light. The effect of these in no case passes away, but leaves 

 its permanent impression on material things, and these impressions, though for many 

 ages they may lie dormant, reappear again at their proper time, and produce their 

 proper effect. Ten thousand centuries ago the sunbeams fell on the leaves of trees, 

 and decomposed carbonic acid just as they do now ; and the woody matter they pro- 

 duced was buried in the earth. In natural affairs no such thing as a system of expe- 



