354 FRAGMENTS OF SCIENCE. 



your hand will repel the red component of your sus- 

 pended strip; but then it will attract the green, and, 

 the forces being equal, they neutralise each other. In 

 fact, the least reflection shows you that the strips will 

 be as indifferent to each other as two unmagnetised 

 darning-needles would be under the same circum- 

 stances. 



But suppose, instead of mixing the colours, we 

 painted one half of each strip from centre to end red, 

 and the other half green, it is perfectly manifest that 

 the two strips would now behave towards each other 

 exactly as our two magnetised darning-needles the 

 red end would repel the red and attract the green, the 

 green would repel the green and attract the red; so 

 that, assuming two colours thus related to each other, 

 we could by their mixture produce the neutrality of an 

 unmagnetised body, while by their separation we could 

 produce the duality of action of magnetised bodies. 



But you have already anticipated a defect in my 

 conception; for if we break one of our strips of wood 

 in the middle we have one half entirely red, and the 

 other entirely green, and with these it would be im- 

 possible to imitate the action of our broken magnet. 

 How, then, must we modify our conception? We 

 must evidently suppose each molecule of tlie wood 

 painted green on one face and red on the opposite one. 

 The resultant action of all the atoms would then ex- 

 actly resemble the action of a magnet. Here also, if 

 the two opposite colours of each atom could be caused 

 to mix so as to produce white, we should have, as be- 

 fore, perfect neutrality. 



For these two self -repellent and mutually attractive 

 colours, substitute in your minds two invisible self- 

 repellent and mutually attractive fluids, which in or- 

 dinary steel are mixed to form a neutral compound, 



