80 FEAGMENTS OF SCIENCE. 



ing the inert stones, and, guided by the volition, the 

 skill, and possibly at times by the whip of the architect, 

 placing them in their proper positions. The blocks, in 

 this case, were moved and posited by a power external 

 to themselves, and the final form of the pyramid ex- 

 pressed the thought of its human builder. 



Let us pass from this illustration of constructive 

 power to another of a different kind. "When a solution 

 of common salt is slowly evaporated, the water which 

 holds the salt in solution disappears, but the salt itself 

 remains behind. At a certain stage of concentration 

 the salt can no longer retain the liquid form; its parti- 

 cles, or molecules, as they are called, begin to deposit 

 themselves as minute solids so minute, indeed, as to 

 defy all microscopic power. As evaporation continues, 

 solidification goes on, and we finally obtain, through 

 the clustering together of innumerable molecules, a 

 finite crystalline mass of a definite form. What is 

 this form? It sometimes seems a mimicry of the archi- 

 tecture of Egypt. We have little pyramids built by 

 the salt, terrace above terrace from base to apex, form- 

 ing a series of steps resembling those up which the 

 traveller in Egypt is dragged by his guides. The hu- 

 man mind is as little disposed to look without ques- 

 tioning at these pyramidal salt-crystals, as to look at 

 the pyramids of Egypt, without enquiring whence 

 they came. How, then, are those salt-pyramids built 

 up? 



Guided by analogy, you may, if you like, suppose 

 that, swarming among the constituent molecules of the 

 salt, there is an invisible population, controlled and 

 coerced by some invisible master, placing the atomic 

 blocks in their positions. This, however, is not the 

 scientific idea, nor do I think your good sense will 

 accept it as a likely one. The scientific idea is, that 



