ASTRONOMY AND METEOROLOGY. 375 



reached by the horizon. There is also in almost all these lateral changes a 

 striking coincidence between the character and extent of the change and the 

 change of place of the spectator with regard to the ecliptic. If I was on the 

 southern side of the ecliptic, though my left itself might be north, the lateral 

 changes were in the southern side of the zodiacal light ; if I was on the north 

 of the ecliptic these lateral changes were on the northern side of the zodiacal 

 light. If, in the course of four or five hours, the earth's rotation carried me 

 from the southern to the northern side of the ecliptic or the opposite, the zo- 

 diacal light changed with me, its lateral boundaries shaping themselves accord- 

 ing to my change of place. This was not always the case, but it was the 

 general fact. When I was far in southern latitudes the greater mass of the 

 zodiacal light, instead of being on the northern side of the ecliptic as here, 

 had shifted over to the south ; and as we came from Rio to New York, as 

 rapidly as steam could carry us, the mass of light came with us to the north 

 once more ; still, however, in its varying positions having a reference to my 

 position with regard to the ecliptic. I ask, supposing that the zodiacal light 

 is from a solar ring, which would make the base of its light at its first and 

 last appearance, nearly or quite 180,000,000 miles off, would that light at its 

 base show such changes as it actually does in half an hour or an hour, when the 

 spectator's place on the earth has been so slightly changed ? I have taken a 

 few of my observations, and have submitted them to calculation, not making 

 much of a selection, for almost every observation in the book would give 

 similar results. 



On September 4, 1854, lat. 22 18' N., last morning observation at 4k 

 30m.: sun rose at 5h. 48m.*; angle between the sun and my horizon conse- 

 quently 19 30'; supposing a ring around the sun reaching to the earth, my 

 horizon would then cut it at a distance of 179,000,000 of miles. From 3h. 30m. 

 to 4h. 30m., the lateral change in the zodiacal light boundaries at tho horizon 

 was 4, or 16.000,000 of miles, while my own lateral change on the globe 

 with reference to the ecliptic in that time had been but 240 miles. Query, 

 could any amount of change of the spectator on our globe have produced 

 that lateral change of 16,000,000 of miles at the base of the zodiacal light, 

 179,000,000 of miles distance? 



January 30, 1851, in the morning, lat. 26 10' N., my last observation at 

 5 o'clock: sun rose at 6h. 50m.; on the former supposition, distance of the 

 base of zodiacal light at 5h. 168,000,000 of miles; my lateral change on the 

 globe from 4,000 to 5,320 miles; the lateral change in the zodiacal light if 

 round the sun 35,000,000 miles. 



November 20, lat. 36 17' N., morning, last observation at 5 : sun rose at 

 6h. 46m. ; base of zodiacal light at 5, 170.000,000 miles; my own lateral change 

 toward the ecliptic from 4 to 5, 240 miles ; lateral change in the zodiacal light 

 at its base 16,300,000 miles. 



January 9, 1855, evening lat. 8 47' N. : sun set 5h. 52m.; first observa- 

 tion at 7h. 20m., next at 8 o'clock; base of zodiacal light at first observation 

 distant 176,000,000 miles; lateral change there in 40' 7,684,000 miles; my 

 own lateral change on the globe, 180 miles. 



* I use apparent time. 



