190 OBSERVATIONS ON THE ZODIACAL LIGHT. 



No. 95. 



JANUARY 2d, 1854: MORNING. 



Lat. 22? IS'N.: Lon. 114= 10' E. 



Sun rose 6/1. 43m. 



Stronger Light 2A. Om. Diffuse OA. 30m. 

 30 10 



40 20 



50 30 



5 10 40 



5 25 50 



"Western Zodiacal Light Oh. 15m. and 1 o'clock. 



The evening of the 31st was cloudy ; yesterday was Sunday. This morning I was on deck a few minutes after 

 midnight, and found the Zodiacal Light, both in the western and eastern sky, as on the 31st a. m. As regards the 

 west-.rn, took outlines at 0" 15"' ; the Light was very dim; I thought that between and co Arietis, it 'was equal to 

 that of the Milky Way about cr, ", and to Andromedse. At 12'' 30 m , it seemed to be more decided than the Zodiacal 

 Light in the eastern sky, but this was probably not real. At I 1 ', it could still be seen; its limits, as in the morning 

 chart at 12" 15 m . At 2'' nothing of it left. Query does it die out, or remain to sink under the horizon? To-night 

 I thought the former. The Pleiades, its upper end, were, however, approaching the horizon at 2 o'clock, and its 

 disappearance might have been owing to the horizontal haze or dimness. 



The night was a most favorable one; stars were bright ; scarcely a breath of air stirring. 



At 12'' 10'", there seemed to be a dim Zodiacal Light in the eastern sky. I was not then fully decided about it, 

 but, as afterwards I saw it gradually growing into the certain Zodiacal Light, of which at 1 o'clock there could be no 

 doubt, I felt satisfied that this at 12" 10'" was truly that Light. At 2 h the Stronger Light was decided enough to 

 give boundaries. For the rest, see chart. The sinking of the Stronger Light at 5 1 ' 10 m , was remarkable: it was so 

 sudden, as was also the change in the strength of the Light. At 5 h I was admiring its brilliancy, and thought it 

 was stronger than at any previous time that morning; just before 5 h 10"", it began to sink, and in two minutes' time 

 had got to the limits given in the chart (marked 5 1 ' 10'"), and had lost more than half of its intensity : it was, indeed, 

 now rather dim. At 5" 25 m , it had got still lower same strength as at 5" 10 1 ". At 5 h 33'" dawn had come. While 

 the Stronger Light was changing thus, the Diffuse remained the same as before, both in strength and boundaries. 



[P. S., lS5fi. I had prepared my chart with both the eastern and western Zodiacal Light upon it, at 12" 15"' and 

 I o'clock, but find it impossible to enter it in this bunk. The vertices of the eastern and western Lights were then 75 

 apart, not cusp-shaped, but rcmnded upwardly. The western Light extended to the Pleiades, and at its base reached 

 1^ N., and 15 S. of the ecliptic.] 



