OBSERVATIONS ON THE ZODIACAL LIOUT, 



No. 306. 



MARCH 20th, 1855 (18th was Sunday): MOBJJI.VG. 



Lat. 23 55' S.: Lon. 4:i r - IV W. 

 Sun rose at 6ft. 7m. 



( 2/i. 0?n. 



Stronger Liht at 4/i. low. and 4/i. 311m.: Diffuse? 4 l:i 



( 4 3D 



Yesterday morning was cloudy, so also last evening. This a. m. went on deck at 2 o'clock, to examine carefully 

 with reference to the light seen in the morning at our farthest .southern latitude. Found at that hour a decided 

 Zodiacal Light impressed on the sky, and with the limits on the right at a a. This Light was very decided, and 

 also its boundary. On the left it increased gradually in strength towards a and ft Capricorn! ; but, on that side, 

 I could not get any reliable boundaries, neither could I make out any decided boundaries for the Stronger Light, it 

 passed so gradually into the Diffuse. Was up again at 3'' 3CP; but clouds interfered till 4 h 15'", when I had an excel- 

 lent sky for observations ; the Stronger Light was at this time very strong, with boundaries well marked, and fully 

 reliable. In the chart is a remarkable change of the left boundary of the Stronger Light, between 4 h 15 and 4" 30 ro : 

 so singular and remarkably great as to be at first sight quite doubtful (see chart). But there was a similar change 

 yesterday morning ; and to-day I gave particular attention to it, and, as the boundaries both at 4" 15 m and 4 1 ' 30'" were 

 very decided, I think there cannot be any doubt on the subject. Of the other boundaries there was not any change 

 in this period. At 4 h 30, the Stronger Light was extremely brilliant ; but this effulgence, instead of being only 

 near the horizon, as formerly, extended up in a conical form quite to the upper extremity of the Light, tapering off, 

 however, in intensity as it ascended. 



