66 FKAGMENTS OF SCIENCE. 



molecules of the crystals fall asunder, so as to leave 

 behind them these exquisite forms. We have here a 

 process of demolition which clearly reveals the reverse 

 process of construction. In this fashion, and in strict 

 accordance with this hexangular type, every ice molecule 

 takes its place upon our ponds and lakes during the 

 frosts of winter. To use the language of an American 

 poet, ' the atoms march in tune,' moving to the music 

 of law, which thus renders the commonest substance in 

 nature a miracle of beauty. 



It is the function of science, not as some think to 

 divest this universe of its wonder and mystery, but, as 

 in the case before us, to point out the wonder and the 

 mystery of common things. Those fern-like forms, 

 which on a frosty morning overspread your window- 

 panes, illustrate the action of the same force. Breathe 

 upon such a pane before the fires are lighted, and reduce 

 the solid crystalline film to the liquid condition ; then 

 watch its subsequent resolidification. You will see it all 

 the better if you look at it through a common magni- 

 fying glass. After you have ceased breathing, the film, 

 abandoned to the action of its own forces, appears for a 

 moment to be alive. Lines of motion run through it ; 

 molecule closes with molecule, until finally the whole 

 film passes from the state of liquidity, through this 

 state of motion, to its final crystalline repose. 



I can show you something similar. Over a piece 

 of perfectly clean glass I pour a little water in which 

 certain crystals have been dissolved. A film of the solu- 

 tion clings to the glass. By means of a microscope and a 

 lamp, an image of the plate of glass is thrown upon the 

 screen. The beam of the lamp, besides illuminating 

 the glass, also heats it ; evaporation sets in, and at a 

 certain moment, when the solution has become super- 

 saturated, splendid branches of crystal shoot out over the 



