THE SUN'S TRUE ATMOSPHERE. 1 09 



hoped to obtain evidence respecting that shallow at- 

 mospheric envelope which Secchi believed in and 

 Lockyer rejected ; though it is quite possible he merely 

 desired to ascertain whether the constitution of the 

 lower part of the sierra differed in any marked respect 

 from that of the upper portion. As the moment 

 approached when the last fine sickle of sunlight was to 

 be obscured, the solar spectrum which was visible in 

 the spectroscopic field of view grew rapidly fainter. 

 The region actually examined by Professor Young was 

 in reality a narrow, almost linear space, touching the 

 edge of the sun's disc; so that before totality had com- 

 menced he had the light from our own illuminated 

 atmosphere, and not direct sunlight, to deal with. 

 Thus he had just such a solar spectrum as is seen when 

 a spectroscope is directed to the sky in the daytime. 

 But as the moment of totality drew near, the illumina- 

 tion of the atmosphere, and with it the brightness of 

 the rainbow-tinted streak, rapidly diminished. At last 

 the solar spectrum vanished ; and then What was it 

 replaced by ? What was found to be the spectrum of 

 the solar atmosphere close by the sun's surface? In 

 place of the rainbow-tinted riband crossed by thousands 

 and thousands of dark lines, there appeared a new and 

 most beautiful spectrum a riband of rainbow-tinted 

 lines, thousands in number and of all degrees of thick- 

 ness, hundreds of red lines, and then, in order, 

 hundreds of orange lines, hundreds of yellow, green, 

 indigo, and violet lines, like coloured cross-threads on a 

 black riband, only infinitely more beautiful. A charm- 



