304 



PROCEEDINGS OF THE AMERICAN ACADEMY 



Singularly enough I find a similar mark on the southern border of 

 the equatorial belt, exactly represented in a drawing by Mr. Camille 

 Flammarion, made on April 22, 1874, in Paris, and published in 

 " Les Terres du Ciel," fig. 174, page 479. But unfortunately the time 

 is not given; and, thus far, I have been unable to obtain it from its 

 author. By assuming that the observation was made at eight o'clock, 

 Paris mean time, and adopting the period of rotation of the similar 

 mark observed by me in 1877-78, it is found that Mr. Flammarion's 

 marking comes within fifty minutes of time of the place it should 

 have occupied had it been the same object as that observed by me. 

 Notwithstanding its disappearance in 1876, it does not seem unlikely 

 that this is the same marking I observed three years later, or at least 

 a recurrence of the same form at the same place, as it might be con- 

 ceived to happen sometimes by the renewal of the same local causes. 



Below is a table giving the dates and times of the passages of mark- 

 ins D on the central meridian. 



On June 20, 1877, the mark D had its form greatly altered, and 



