330 COMBINATION OF FORCES. 



find a sufficient number of common properties to warrant 

 our classing them in one family. 



The dream of the alchemists, in the vain endeavour 

 to realise which they exhausted their lives and dissipated 

 their wealth, had its foundation in a natural truth. The 

 transmutation of one form of matter into another may 

 be beyond the power of man, but it is certainly con- 

 tinually taking place in the laboratory of nature, under 

 the directing law of the great Creator of this beautiful 

 earth. 



The speculations of men, through all ages, have leaned 

 towards this idea, as is shown by the theory of the four 

 elements, Air, Fire, Earth, and Water, of the ancients, 

 the three, Salt, Sulphur, and Mercury, of the al- 

 chemists, and the refined speculations of Newton and 

 Boscovich on the ultimate constitution of matter. All 

 experimental inquiry points towards a similar conclu- 

 sion. It is true we have no direct evidence of any 

 elementary atom actually undergoing a change of state ; 

 but when we regard the variations produced by electrical 

 influence, the changes of state which arise from the 

 power of heat, and the physical alterations produced by 

 light, it will be difficult to come to any other conclusion 

 than that the particles of matter known to us as ultimate 

 are capable of change, and consequently must be far 

 removed from positively simple bodies, since the real 

 elementary atom, possessing fixed properties, cannot be 

 supposed capable of undergoing any transmutation. 

 Allotropism could not occur in any absolutely simple 

 body. 



It will now be evident that in all chemical phenomena 

 we have the combined exercise of the great physical 

 forces, and evidences of some powers which are, as yet, 

 shrouded in the mystery of our ignorance. The forma- 

 tion of minerals within the clefts of the rocks, the 

 decomposition of metallic lodes, the germination of 



