OBSERVATIONS OF LUNAR OBJECTS. 283 



Mr. Elger's diagram of this date fuU)^ confirms the observations by Mr. Gled- 

 hill of the streaks /3 and rj, and their parallelism with a in September and 



Plato, Dec. 15, 1869.— T. G. E. Elger. 



October. I believe this to be Mr. Elger's first observation of these streaks. 

 Taking into consideration the difl"erence of apertures, were they first within 

 reach of the smaller aperture of 4 inches on this day (December 15) ? If so, 

 did they become brighter during the interval that elapsed since Mr. GledhiU 

 first saw them ? At the close of the October (1869) observations, Mr. Gledhill 

 furnished the following information : — " Parallel streaks on N.E. floor. I have 

 gone over all my observations, and find that y (see fig. 9, ante, p. 263) has 

 always been seen except at sunrise and sunset. /3 appears in my observations for 

 the first time September 25, 1869, about 11 hours. At this time the light sector 

 passed beyond spot No. 4, and had its apex about spot No. 3. It was also seen 

 at this point again on October 21 at 12 hours." [Was there any connexion be- 

 tween the sector extending as far as spot No. 3 and the streak /3 emanating 

 from the same spot, as if the spot or group had been in eruption ? The very 

 short extension of the streak /3 seen once or twice by Mr. Gledhill beyond 

 spot No. 3 towards the S.W. is curious, as if it were an outflow in that direction 

 which could not proceed in consequence of the rising of the ground.] Mr. 

 Gledhill farther remarks : — " I saw fi a few hours before sunset on Plato on 

 the 27th of September, 1869, and also the sector and some other streaks. 

 The streak rj was first seen by me about 11 hours on October the 19th, 1869. 

 It comes from that fine summit on the crater-wall (the rock ^ of B. and M.) 

 which casts the long shadow on the plain at sunset. The streak /3 I think 

 comes from a portion of the inner slope, which is often highly illuminated ; 

 /3 and »/ are nearly always seen now. [Mr. Gledhill appears to regard these 

 streaks as emanating from the waU. Is it not more likely that jj emanates 

 from spot No. 4, and j3 from spot No. 3 ? — W. E. B.] On the evening of De- 

 cember 15,1869, Mr. Gledhill recorded the streak ft as fairly bright, and »? 

 as faint near spot No. 4, ■\\dth a broad brighter base, which is, as mentioned 

 elsewhere, quite in accordance with phenomena of eruption from spot No. 4. 

 I have made the following remarks on the form containing Mr. Gledhill's 

 observations : — " jj, which, if I remember rightly, Mr. Gledhill first saw as a 

 narrow streak, to-night is described as broad, with bright base, faint near 

 spot No. 4. Mr. Elger on the same evening described a ' fan ' of light from 



