t ORIGIN OF THE WORLD 



This would imply that dark stars must be more nu- 

 merous in the universe than bright ones. 



INVISIBLE NEBULAE 



And this suggests a query as to whether there may : 

 not also be non-luminous nebulae in the heavens. 

 This seems probable enough; indeed the puzzling 

 thing is rather that so many nebulae are visible. But 

 until very recently no direct evidence of the existence 

 of dark nebulae was forthcoming. Early in the 

 present century, however, some novel observations 

 were made which may be most plausibly explained on 

 the supposition that a dark star had plunged directly 

 through the mass of an invisible nebula. 



If our inferences are correct, the catastrophe in 

 question really occurred about the year 1600, just at 

 the time, let us say, when the Pilgrim Fathers were 

 planning to migrate to America. But the colliding 

 bodies lie so far distant in stellar space that the light 

 waves with which the disaster was signaled forth re- 

 quired about 300 years to reach our planet. Thus it 

 happened that one night in February, 1901, it was re- 

 corded in terrestrial observatories that a new star had 

 flashed suddenly forth in the constellation Perseus. 

 Night by night this star became brighter until it 

 equaled stars of the first magnitude in brilliancy. 

 Then it gradually faded away. In the course of a few 

 months it became invisible to the naked eye, and in 

 the succeeding years it has remained at about the 

 twelfth magnitude, near the limits of vision of all but 

 the largest telescopes. 



But as the star diminished in brilliancy there was 

 3 25 



