The Lunar Eclipse of September 13. 223 



42m. — 8th. I. egress, 6h. 11m. II. ingress, 6h. 56m. I. shadow 

 egress, 7h. 10m. II. shadow ingress, 8h. 55m. II. egress, 

 9h. 49m. Ditto shadow, llh. 46m. — 10th. III. ingress, 7h. 

 44m. IV. egress, lOh. 7m. III. egress, llh. 22m. III. shadow 

 ingress, llh. 53m. — 13th. I. ingress, llh. 13m. Ditto shadow, 

 12h. 18m. — 15th. I. shadow ingress, 6h. 46m. I. egress, 

 8h. 0m. Ditto shadow, 9h. 6m. II. ingress, 9h. 22m. Ditto 

 shadow, llh. 34m. II. egress, 12h. 15m. — 17th. III. ingress, 

 llh. 20m. — 22nd. I. ingress, 7h. 30m. Ditto shadow, 8h. 42m. 

 I. egress, 9h. 50m. Ditto shadow, llh. lm. II. ingress, llh. 

 50m. — 26th. II. shadow egress, 6h. 22m. — 27th. IV. shadow 

 ingress, 9h. 21m. — 29th. I. ingress, 9h. 22m. Ditto shadow, 

 lOh. 37m. — 31st. I. egress, 6h. 9m. Ditto shadow, 7h. 25m. 



OCCULTATIONS. 



Oct. 15th. /Tauri, 4 mag. 7h. 38m. to 7h. 45m.— 16th. 

 2 Tauri, 4h mag., 7h. 25m. to 8h. 9m. l Tauri, 4| mag. 7h. 

 33m. to 8h. 80 Tauri, 6 mag., 7h. 55m. to 8h. 36m. 81 Tauri, 

 5i mag., 8h. 6m. to 8h. 51m. 85 Tauri, 6 mag., 8h. 33m. to 

 9h. 27m. 



THE LUNAR ECLIPSE OF SEPTEMBER, 13. 



BY JOHN BJROWNING, F.PwA.S. 



During this eclipse several facts were noted that, carefully 

 considered, may, I think, tend to elucidate the interesting 

 problem of the condition or constitution of the Moon's surface. 

 Few questions are more interesting to astronomers, and few 

 seem more difficult of solution. 



It is because of their indirect bearing upon this question 

 that I think the points I am about to describe merit particular 

 attention. On the 13th of September the sky during the day 

 was overcast, and it remained thick until shortly before nine 

 o'clock. Then, quite suddenly, it became exceedingly clear, 

 and remained so for the greater part of the night. After the 

 very unfavourable weather astronomers have lately had to 

 contend with, and the tantalizing obscurity which prevailed on 

 the night of the disappearance of the whole of Jupiter's 

 satellites, except in large telescopes, the effect of this almost 

 unlooked-for clearness was most cheering-. This exceeding- 

 clearness probably materially modified the results that were 

 afterwards obtained. 



According to calculation, the eclipse must have commenced 



