40 OBSERVATIONS ON THE ZODTACAL LIGHT. 



No. 20. 



JULY 1st, 1853 : EVBXIMI. 



Lat. 26 10' N.: Lon. 127^ 42' E. 



Sun set at 6A. Slim. 



Stronger Light at 8/1. 30m. Diffuse at S.'i. 30m. 

 90 90 



9 30 9 30 



10 30 

 Sun's Longitude, !)!) 2S'. 



Had very good observations of the Zodiacal Light. Dr. - - and Mr. S - were with me at half-past 

 8, and Loth agreed in the inferior darkness ("blueness" they called it) of the sky, and the inferior brilliancy of the 

 stars within the wide limits already noticed. I got them to give the boundaries, and we all agreed in them as 

 given in the chart in the outer, or dotted line, a. u. 



At that time the gauzy light showed itself within the lint- of dashes, and the Stronger Light within the 

 full line, marked for that hour; and so with, the other hours. At 10 h 30 m there was no Stronger Light. At 11 

 o'clock there was only a dim marking of light about 4o Virginis, of which I could not get the boundaries. All 

 through the evening the light passed oil', at the right, into something which did not sceui to be the Zodiacal Light, 

 but stretched along the horizon in a space about G wide, till it met the Milky Way. 



[P. S., December 9, 1853. The character of the Zodiacal Light for this season seems to have better developed 

 itself on this evening; and the charts from this on, for some time, have three kinds of boundaries: 1st. The dotted, 

 giving the boundaries of the sky where it is simply made pale, without any positive light; 2dly. The lines of 

 dashes, showing where the positive light ("Diffuse") commences; and lldly. The full lines, giving the boundary of 

 the "Stronger Light." Something of this kind seems to have shown itself on the evening of the 20th; but it, was 

 new, and we only get hints of it in the chart of that evening.] 



