84 FRAGMENTS OF SCIENCE. 



delicate, silent action of this beam within the ice that I 

 now wish to direct your attention. Upon the screen is 

 thrown a magnified image of the slab of ice : the light of 

 the beam passes freely through the ice without melting it, 

 and enables us to form the image, but the heat of the 

 beam is in great part intercepted by the ice, and that heat 

 now applies itself to the work of internal liquefaction. 

 Observe those stars breaking out over the white surface, 

 and expanding in size as the action of the beam continues. 

 These stars are liquefied ice, and each of them, you ob- 

 serve, has six rays. They still more closely resemble 

 flowers, each of six petals. Under the action of the heat 

 the molecules of the ice fall asunder, so as to leave be- 

 hind them these exquisite forms. We have here the pro- 

 cess of crystallization reversed. In this fashion, and in 

 strict accordance with this hexangular type every ice mole- 

 cule 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 Na- 

 ture a miracle of beauty. 



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

 this universe of its wonder and its mystery, but, as in the 

 case here 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, illus- 

 trate the action of the same force. Breathe upon such a 

 pane before the fires are lighted, and reduce the solid crys- 

 talline film to the liquid condition, then watch its subse- 

 quent appearance. 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, 



