CLOUDS AND RIVERS, ICE AND GLACIERS. 



37 



portion ? The dark heat of the sun. The great body 

 of the light waves and even a portion of the dark ones, 



LIQUID FLOWERS IN LAKE ICE. 



pass through the ice without losing any of their heating 

 power. When properly concentrated on combustible 

 bodies, even after having passed through the ice, their 

 burning power becomes manifest. 



103. And the ice itself may be employed to con- 

 centrate them. "With an ice-lens in the polar regions 

 Dr. Scoresby has often concentrated the sun's rays so 

 as to make them burn wood, fire gunpowder, and melt 

 lead ; thus proving that the heating power is retained 

 by the rays, even after they have passed through so cold 

 a substance. 



104. By rendering the rays of the electric lamp 

 parallel, and then sending them through a lens of ice, 

 we obtain all the effects which Dr. Scoresby obtained 

 with the rays of the sun. 



