140 LIGHT SCIENCE FOR LEISURE HOURS. 



made at a distance of several degrees from the sun, a 

 * dark disc ' being so arranged as to conceal * a circular 

 space extending a degree or so beyond the eclipsed 

 sun ' all round. During the eclipse of 1870, in antici- 

 pation of which this suggestion was made, Professor 

 Newcomb endeavoured to observe the zodiacal light in 

 this way. But he was not successful ; in fact, the sky 

 was hazy and the circumstances in other respects 

 unfavourable for an observation of the kind. On the 

 present occasion, however, he has applied the method 

 successfully. ' Professor Newcomb,' we read, * who had 

 erected a screen on a high pole, thinks he detected 

 the zodiacal light extending six degrees from the 

 sun.' The telegram containing this passage comes 

 from an observer who would be likely to place very 

 little faith in an observation of the zodiacal light 

 during total eclipse, as he had, in fact, adopted the 

 opinion that the zodiacal light is a terrestrial phe- 

 nomenon. Professor Newcomb would be the last in 

 the world, I think, to describe an observation in 

 terms so vague, and we should not be at all surprised 

 to learn that he was quite satisfied with his recognition 

 of the zodiacal light. The observation is one which 

 will probably be renewed on future occasions. It may 

 turn out that the zodiacal light, like the corona, varies 

 with the varying condition of the sun as to spots and 

 other signs of disturbance. 



