﻿the Rays producing Aurora Borealis. 215 



Application to Aurora Borealis. 

 The Structure of Aurora*. 



3. According to our present view, in the aurora? we are 

 actually examining the luminosity produced when the electric 

 radiation from the sun strikes the atmosphere, and from the 

 form and structure o£ the luminosity we should be able to 

 examine the way in which the solar radiation is absorbed by 

 matter. In certain cases the form and structure is so cha- 

 racteristic and definite that we should be able to find out 

 some definite properties with regard to the law of absorption 

 of solar rays, and perhaps to identify them with some sort of 

 known electric radiation. 



One of the most conspicuous forms of aurora, showing 

 very characteristic and definite properties, are no doubt the 

 draperies. 



Two drapery forms are represented in fig. 2 ; the one above 



Fie-. 2. 



was observed at Godthaab; 1882, and the one below is from 

 the classic work of P. Gaimard, w Voyages en Scandinavie, 

 en Laponie et an Feroe. 5 



We notice the straight-lined structure, so characteristic 

 for these forms. The simplest interpretation possible of the 

 straight-lined streamers is to suppose thai they mark the 

 track followed by the solar rays as they penetrate down 



