184 OBSERVATIONS ON THE ZODIACAL LIGHT. 



No. 92. 



DECEMBER 30th, 1853 : MORNING. 



Lat 22-' IS' N.: Lon. 11-P 10' E. 



Sun rose 6A. 43m. 

 Stronger Light 3/i. Om. Diffuse 3h. Om. 



3 30 3 30 



4 30 4 30 



5 20 Paled sky 4 30 

 5 25 



Sun's longitude 278 47'. 



Morning sky fine and clear. Intended to b? up at 1" SO" 1 , but was not waked till near 3' 1 . Took boundaries as in 

 the chart. At 3", the Stronger Light was faint, the Diffuse very distinct. This last, at all this morning's observa- 

 tions, seemed to run up to Prresepc, coming nearly to a point there: but I could not be certain about it, and have 

 put ? to the doubtful lines. The Zodiacal Light was strongest at about 4" 30 : ". At this hour (4" 30'"), I was sur- 

 prised to find that the Diffuse Light on the left, or north, had greatly extended its boundaries, running through the 

 middle of Corona Borealis. I have, for that hour, given, with the Stronger and the Diffuse Light, also this latter ex- 

 tension, marked by dots andaaa, though it \vas so strung as t:> be very little different from the Diffuse Light itself. I was 

 not looking lor this; but I now remember a similar sudden extension, northwardly, in the evening Light of the 1st 

 of July. Tins is in the same part of the sky. and is probably owing to the same cause namely, that the approach 

 of the ecliptic to the horizon brings this nebulous substance more laterally to the eye. There is now. between mid- 

 night and 5 o'clock, a great lessening of the angle of the ecliptic with the horizon, particularly towards 4 or 5 

 o'clock. This extended light is, however, much stronger than that of July, when first seen; being, in this respect, 

 the opposite of that. This extended light seems to reach up to Prassepe ; but as the space between Regains and 

 Prsesepe is quite void of stars above those of the 6th magnitude, I am doubtful of it. Still, there does seem to be a 

 positive whiteness, as of the Zodiacal Light. From 5' 1 20" to 5 h 25"', the Stronger Light sunk rapidly down, and was 

 very much dimmed. At 5 h 32'", the Light broke bounds and spread, and dawn had come. This spreading, however, 

 is not so striking as it was in September and October. 



