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 othe'r 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 
