34 THE FORMS OP WATER IN 



iron filings be scattered over a magnet, each particle 

 becomes also endowed with two poles. Suppose such 

 particles devoid of weight and floatingin our atmosphere, 

 what must occur when they come near each other? 

 Manifestly the repellent poles will retreat from each 

 other, while the attractive poles will approacli and 

 finally lock themselves together. And supposing the 

 particles, instead of a single pair, to possess several pairs 

 of poles arranged at definite points over their surfaces ; 

 you can then picture them, in obedience to their mutual 

 attractions and repulsions, building themselves together 

 to form masses of definite shape and structure. 



95. Imagine the molecules of water in calm cold air to 

 be gifted with poles of this description, which compel the 

 particles to lay themselves together in a definite order, 

 and you have before your mind's eye the unseen archi- 

 tecture which finally produces the visible and beautiful 

 crystals of the snow. Thus our first notions and con- 

 ceptions of poles are obtained from the sight of our 

 eyes in looking at the effects of magnetism ; and we 

 then transfer the^e notions and conceptions to particles 

 which no eye has ever seen. The power by which we 

 thus picture to ourselves effects beyond the range of the 

 senses is what philosophers call the Imagination, and 

 in the effort of the mind to seize upon the unseen 

 architecture of crystals, we have an example of the 

 ' scientific use ' of this faculty. Without imagination 

 we might have critical power, but not creative power iu 

 science. 



