408 Oh the BrigUness of the Corona of Ajjoil 16, 1803. 



vvliere d is the distance from moon's limb given in first column. The 

 distance is thus measured from a point 0*18 = 2'-7 within the circle on 

 the photograph taken as the moon's limb. This is well within the- 

 sun's limb, though near it. It need^'not cause much surprise that the 

 calculated numbers close to the limb exceed the observed; for the 

 corona close to the limb was obscured during part of the exposure- 

 by the advancing moon. Further examination of these points is- 

 required. The following diagrams exhibit graphically the figures of 

 Table III. 



