258 



THE PRINCIPLES OF SCIENCE. 



Variable Properties of Matter. 



I have enumerated some of the few properties of matter, 

 which are manifested in exactly the same manner by all 

 substances, whatever be their differences of chemical or 

 physical constitution. But by far the greater number < 

 qualities vary in degree ; substances are more or ^lesi 

 dense, more or less transparent, more or less compress 

 more or less magnetic, and so on. One very common 

 result of the progress of science is to show that qualities 

 supposed to be entirely absent from many substances are 

 present only in so low a degree of intensity that the 

 means of detection were insufficient. Newton believed 

 that most bodies were not, Affected by the magnet at all 

 Faraday and Tyndall have rendered it very doubtful 

 whether any substance whate cS wholly non-magnetic, 

 including under that term diamagnetic properties, 

 are rapidly learning to believe that there are no sub-| 

 stances absolutely opaque, or non-conducting, non-electric, 

 non-elastic, non-viscous, non- compressible, insoluble, in- 

 fusible, or non-volatile. All tends to become a matter o1 

 degree, or sometimes of direction. There may be som- 

 substances oppositely affected to others, as ferro-magneti 

 substances are oppositely affected to diamagnetics, or ? 

 substances which contract by heat are opposed to tho* 

 which expand; but the tendency is certainly for evei 

 affection of one kind of matter to be represented by some 

 thing similar in other kinds. On this account one ol 

 Newton's rules of philosophizing seems quite to lose al 

 validity ; he said, ' Those qualities of bodies which arj 

 not capable of being heightened and remitted, and whicfl 

 are found in all bodies on which experiment can be mad< 

 must be considered as universal qualities of all bodies 

 As far as I can see, the contrary is more probable, nameW 



