288 



OBSERVATIONS ON TIIE ZODIACAL LIGHT. 



No. 144. 



APRIL 25th, 1854: EVENING. 

 Lat. 34 40' N. : Lon. 138 59' E. 



Sun set Gli. 35m. 

 Stronger and Difl'use Light at 8A., 9/i., and IDA. 20m. 



A fiae clear niglit. 



At 7 h 46 m tlie Zodiacal Light was distinct up to Castor and Pollux ; could not get bound- 

 aries till 7'' 55" 1 , when the Stronger Light was at b. At 8'' 7'" it was very strong, and I began to think that this 

 great and rapid increase of light must Ivlong to pulsations. Watched, therefore, carefully (as the night, very 

 clear, was so for a favorable one), to have further proofs one way or the other. The Milky Way crossing the 

 Zodiacal Light was against such observations ; but I soon became pretty well satisfied that there were pulsations 

 in intensity, and also in the boundary on the right or northern side. My notes, taken at the time, were as follows : 



h. in. 



At 7 55, at b. 



8 7, strong. 



8 10, dimmed, and at a. 



8 15, dim, do. 



8 17, at c, and bright. 



8 22, dvi:'nl<.'illy at c, and bright. 



8 23, do. do. 



8 24, dimming. 



8 24J, at a, and decidedly dimmed. 



8 26, do. do. 



8 28, brightening. 



//. m. 

 At 8 32, at c, and bright. 



8 34, do. and very bright. 



8 36, do. do. 



8 37, do. dimmed. 



8 42, do., seems to be still dim; but there is now so 

 little space between (lie Milky Way and hori- 

 zon, that it is difficult to judge, and I give up 

 observing. 



10 20, the boundaries were apparently as at 9' 1 , but 

 the light was all very dim. 



