MATTER AND FORCE. 391 



ing certain points for attack, round about those points the 

 beam works silently, undoing the crystalline architecture, 

 and reducing to the freedom of liquidity molecules which 

 had been previously locked in a solid embrace. The 

 liquefied spaces are rendered visible by strong illumination. 

 Observe those six-petaled flowers breaking out over the 

 white surface, and expanding in size as the action of the 

 beam continues. These flowers are liquefied ice. Under 

 the action of the heat the 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 magnifying 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 per- 

 fectly clean glass I pour a little water in which certain 

 crystals have been dissolved. A film of the solution 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 supersaturated, splendid branches 

 of crystal shoot out over the screen. A dozen square feet 



