Sun-Spots. 71 



terruptions of continuity in the bright envel- 

 opes immediately surrounding the sun," 

 ''Cavities " etc. 



Overestimate of the Degree of Spot- shadow. 



Public sentiment in regard to the degree 

 of darkness which is disclosed in sun-spots 

 is exceedingly erroneous. It is believed that 

 the spots are really dark. ZOLLNER, however, 

 states that " The black umbra of a spot emits 

 four thousand times as much light as that de- 

 rived from an equal area of the moon." 

 " The blackest part of the spot is intrinsically 

 bright." 



What They are not, and what They are. 



These phenomena may not arise from dis- 

 ruptions taking place on the sun's surface, 

 neither from violent agitations near that sur- 

 face. The essential and intimate character 

 of the so-called sun-spots may be found in 

 the interruptions of continuity in the fluid 

 occupying the solar cone-space. This fluid 

 which we call sunlight intercommunicates 

 between the entire opposing surface of sun 

 and earth, unless interrupted by some tempo- 

 rary cause. Any cause which is capable of 



