260 ( 46 ) 



counsellor. Let me then cast him out, and let me trust- 

 fully assume that you will one and all postpone that 

 balmy sleep, of which dinner might, under the circum- 

 stances, be regarded as the indissoluble antecedent, and 

 that you will manfully and womanfully prolong your in- 

 vestigations of the ether and its waves into regions 

 which have been hitherto crossed by the pioneers of 

 science alone. 



Not only are the waves of ether reflected by clouds, 

 by solids, and by liquids, but when they pass from light 

 air to dense, or from dense air to light, a portion of the 

 wave-motion is always reflected. Now our atmosphere 

 changes continually in density from top to bottom. It 

 will help our conceptions if we regard it as made up of 

 a series of thin concentric layers or shells of air, each 

 shell being of the same density throughout, and a small 

 and sudden change of density occuring in passing from 

 shell to shell. Light would be reflected at the limiting 

 surfaces of all these shells, and their action would be 

 practically the same as that of the real atmosphere. 



And now I would ask your imagination to picture this 

 act of reflection. What must become of the reflected 

 light ? The atmospheric layers turn their convex sur- 

 faces towards the sun ; they are so many convex mir- 

 rors of feeble power, and you will immediately perceive 

 that the light regularly reflected from these surfaces 

 cannot reach the earth at all, but is dispersed in space. 



But though the sun's light is not reflected in this 

 fashion from the aerial layers to the earth, there is indu- 

 bitable evidence to show that the light of our firmament 

 is reflected light. Proofs of the most cogent descrip- 

 tion could be here adduced ; but we need only consider 

 that we receive light at the same time from all parts of 



