270 FRAGMENTS OF SCIENCE. 



But suppose, instead of mixing the colors, we painted 

 one half of each strip from center to end red, and the 

 other half green, it is perfectly manifest that the two strips 

 would now behave toward each other exactly as our two 

 magnetized 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 colors thus 

 related to each other, we could by their mixture produce 

 the neutrality of an unmagnetized body, while by their 

 separation we could produce the duality of action of mag- 

 netized bodies. 



But you have already anticipated a defect in my con- 

 ception; for if we break one of our strips of wood in the 

 middle we nave one half entirely red, and the other entirely 

 green, and with these it would be impossible to imitate the 

 action of our broken magnet. How, then, must we modify 

 our conception ? We must evidently suppose each mole- 

 cule of the wood painted green on one face and red on the 

 opposite one. The resultant action of all the atoms would 

 then exactly resemble the action of a magnet. Here also, 

 if the two opposite colors of each atom could be caused to 

 mix so as to produce white, we should have, as before, per- 

 fect neutrality. 



For these two self -repellent and mutually attractive 

 colors, substitute in your minds two invisible self-repel- 

 lent and mutually attractive fluids, which in ordinary 

 steel are mixed to form a neutral compound, but which 

 the act of magnetization separates from each other, 

 placing the opposite fluids on the opposite face of each 

 molecule. You have then a perfectly distinct conception 

 of the celebrated theory of magnetic fluids. The strength 

 of the magnetism excited is supposed to be proportional to 

 the quantity of neutral fluid decomposed. According to 

 this theory nothing is actually transferred from the excit- 

 ing magnet to the excited steel. The act of magnetiza- 

 tion consists in the forcible separation of two fluids which 

 existed in the steel before it was magnetized, but which 

 then neutralized each other by their coalescence. And if 

 you test your magnet, after it has excited a hundred pieces 

 of steel, you will find that it has lost no force no more, 

 indeed, than I should lose, had my words such a magnetic 

 influence on your minds as to excite in them a strong re- 

 solve to study natural philosophy. I should rather be the 



