FAEADAY SPEAKS OF PROPERTY AS FORCE. 211 



ting anything directive or formative to mere force in 

 all mechanical construction is so plain, that to talk of 

 force turning a chess-man, stamping a die, weaving a 

 web, &c., by itself, would be simply ridiculous. If we 

 wish to convert our purchased velocity into heat, or 

 electricity, or magnetism, it is still plain that we can 

 only do so through the intervention of the pre-existing 

 properties of matter, and in the last we are tied down 

 to narrower limits of the means. In dealing with 

 molecular movements, or forces, we find that although 

 molecules will certainly not move without force, yet 

 they will only move in the way for which they are- 

 fitted to move by their inherent properties or qualities, 

 no matter how the force is furnished. A fluorescent 

 body exposed to the non-luminous, highly refrangible 

 rays of the spectrum, will take on the motion, cer- 

 tainly, but not at the same rate of vibration, and thus 

 give them out as visible light; and we have no 

 power by any manipulation of force to cause the said 

 body to act differently. In fact, neither can it help 

 itself; it is just as passive in its power of directing 

 motion. It is only when we come to chemical action 

 that any difficulty or ambiguity has arisen, and this is 

 simply from the loose way in which the word force 

 has been used to denote property as well as force, and 

 if we carefully distinguish between these, there is no- 

 real difficulty in the question. Unfortunately, even 

 deservedly high authorities have fostered error by in- 

 advertence in this respect. Faraday, for example,, 

 speaks of the conservation of chemical force, and in- 

 stances the unchangeableness of the inherent qualities, 

 which specifically distinguish oxygen from other sub- 



142 



