70 LIGHT SCIENCE FOR LEISURE HOURS. 



of sunlight towards the inner planets, Venus and 

 Mercury. Now suppose the earth were divided into 

 eight equal parts, and each fashioned into a globe. 

 The eight globes would each have a diameter half the 

 earth's present diameter, and each would reflect one- 

 fourth of the light which the earth now reflects. The 

 eight then would reflect altogether twice as much light 

 as the earth actually reflects ; and yet their combined 

 bulk would only equal hers. If each of these eight 

 globes were divided into eight others, four times as 

 much light would be reflected as the earth now reflects. 

 And if the division were continued until the several 

 globes were reduced to mere grains, and these grains 

 were well spread out, the quantity of sunlight which 

 the cloud of grains would intercept and reflect towards 

 the interior planets would exceed many millionfold 

 that which the earth actually reflects. In like manner, 

 an incandescent globe, if divided into myriads of 

 minute incandescent globes, would supply much more 

 light than in its original condition. 



So in the case of the coronal matter. Assuming it 

 to consist of myriads of indefinitely minute particles, 

 very widely dispersed, it would be capable of emitting 

 and reflecting a quantity of light altogether dispropor- 

 tioned to its actual weight regarding it as a whole. 



But when we consider the spectrum of bright lines 

 given by the corona, the case no longer remains 

 altogether so simple. One cannot very readily accept 

 the opinion of Professor Harkness, that this portion of 

 the coronal light comes from iron existing in the state 



