598 OBSERVATIONS ON THE ZODIACAL LIGHT. 



No. 299. 



MARCH let, 1355: MORNING. 



Lat. at 3k., 39 11' S. : Lon. 57 12' W. 



Sun rose at 5/<. 4~\m. 

 Stronger and Diffuse Light at 3 o'clock. 



The sky cloudless, and extremely favorable for observations down to the very horizon, where stars showed themselves 

 immediately after passing its edge. I was on deck when the moon set, about 2 h 30'"; but the sky was a long time in 

 darkening afterwards ; and I could not get fully reliable boundaries till 3 o'clock. Those given in the chart for the 

 Stronger Light may be entirely relied on. Those of the Diifuse, on the left, were imperfectly marked ; and, on the 

 right, they were also not easily made out. I thought I observed pulsations in intensity. There was- a portion 

 bounded by the zigzag x x far brighter than the rest, and of this I made these records :* 2' 1 58'" very bright ; so to 

 3 h 8i m , when extremely bright; 3'' lH m , just dimmed greatly; 3 h 19'", just now brightened; 3" 21 m , very bright : 

 3" 26 m , exceedingly so ; no further change till near dawn (3 h 20'"), when it sunk down and dimmed, apparently the 

 eifect of dawn, which had come decidedly at 3" 31. 



This was a very good observation, and the boundaries may be considered fully reliable. 



It ought to be noticed that, owing to our rapid change of longitude, my watch was five or six minutes too slow ; 

 the times given above, therefore, need correction. 



a Previous to 2A. 58m. I thought, sometimes, I saw changes of intensity ; but was so uncertain, that I concluded it best not to record them. 



