648 OBSERVATIONS ON THE ZODIACAL LIGHT. 



Ko. 324. 



APRIL 17th, 1855: 



Lat, at 4ft., 27 59' N. : Lnn. 62 26' W. 



Sun rose at 5'i. 37 . 



Stronger and Diffuse Light at 3A. 15i. and 4ft. 15m. 

 Zenith point at 3ft. 15u , Lat. 51 27' N, : Lon. 50 50'. 



The sky was very favorable, but the Zodiacal Light is now so dim as to make it very difficult to get reliable 

 boundaries. Even at 4 h 15 m , the boundaries of the upper part of even the Stronger Light could not easily be made 

 out. I am, however, using the greatest care in getting outlines, both at evening and morning, on account of their 

 importance for comparisons with those south of the equator. This morning, as yesterday, soon after 3 h 30"", a bright 

 light began to grow up until it reached the boundary a a in the chart ; afterwards, towards 4 h 37, the Light within 

 the zigzag b b became exceedingly brilliant, as if the sun were just going to rise there. About 4 h 41' this appeared 

 to dim considerably ; at 4' 1 43 m dawn had come. 



