196 Brightness of the Satellites of Uranus. 
Dr. H. C. Vogel has suggested that Titania also is of varying 
brightness in different parts of the orbit. arly attention was 
ven to this point. The following extracts from the observing 
Cooke may be of use, when an exact photometric determination 
comes to be made. The weight indicates the steadiness of the 
images, five being perfectly steady. The epee given are to 
the nearest degree in p and nearest second in s. 
1875. Jan. 26. Titania; p=260°, s=19”. We 4, Titania is 
fainter than I have ever seen it—HN. 
1875. March 4. Four stars visible besides Oberon and Titania. 
Oberon, p23ie: s= 26° 
Titania, p= 184° gosz 85" 
Star 1, p= 350°+ s= 80° 
Star 2, p= 20° s= 100’4 
Star 3, p= 130°+ s=130°4+ 
Star 4, p= 95°+ $= 200°+ 
Order of brightness ; 4, 1, 8, 2; and 2 somewhat brighter than 
Titania.—HN. 
1875. May 25. Oberon: p=230°, s=31”. 
Titania: p=21°, s=30". 
on very faint [and therefore as nothing is said of bright- 
-_ ci ptsies Titania brighter than Oberon at same dis- 
S76. fan. 14. Oberon: p=11°, s=28"") 
Titania: p=48°, s=2T7" § 
Titania much brighter than Oberon. Moonlight.—HN. 
1376. Jan. 20. Oberon: p=821°, s=27” 
Titania : p= 186°, s=34” 
| Ser of Oberon quite difficult [and of Titania not so. }—HN. 
1876. Jan. 25. — ; p=181", s=44” Wt=2. 
= 852°, s=31" 
Oberon easier = see (brighter) than Titania.—HN. 
1876. Jan. 26. Titania in p=310°, s=16”. Wt. 5. 
— is son the smallest distance at which Titania has been 
1876. Jan. 31. ~— a =716°, s=17” | w 
riel: p=29°, s=12” Sut 
Titania is at ot twice as bright as Ariel. Ti ~— is 
decidedly brighter than the satellite of Neptune. It is easier 
to see (under these conditions, Wt=5) within 16” of Tenino: 
than the satellite of Neptune within 16” of Neptune.—HN. 
1876. Feb. 2. Oberon : p=888°, s=88" | 
tlania; p=T°, s= =34"{ 
After careful examination with 800 A and 400 A, I cannot 
decide which is brighter, Oberon or nee but if there is any 
differe’ Titania is the brighter.— 
