376 ANNUAL OF SCIENTIFIC DISCOVERY. 



March 16, 1855, evening, lat. 22 55' S.. sunset 6k. 12m.; first observa- 

 tion at 7h. 30m. ; next at 8 ; next at 8k. 30m. Rise of zodiacal ligkt at 7k. 30m. 

 distant 176,000,000 miles; lateral ckange in its ligkt in kalf an kour 60, in 

 an kour 135 miles. 



Tkese figures, I wisk to say are the result in part of inspection or measure- 

 ment on tke ckart ; but tkey are sufficiently near for our use ; and I put tke 

 query wketker a solar ring can be supposed to meet tke data of tke case ? 

 An eartk-ring will do it ; tkat is, a nebulous ring around tke earth will readily 

 allow suck lateral ckanges to be produced by suck a ckange of tke spectator's 

 place. 



But tkere is anotker view of tkis subject wkick may be considered still 

 more conclusive against suck a solar ring. Take cases wkick very often occur 

 wken tke ecliptic is somewkere toward a rigkt angle to tke korizon, and cir- 

 cumstances tkerefore favorable for a good display of tke zodiacal ligkt. Say 

 it is morning, an kour and a kak" before sunrise. Tke base of tkis ligkt will 

 be exceedingly brilliant as muck so almost as if tke sun were just going to 

 rise wkile tke vertex of tke kgkt overkead will be so dim as scarcely to be 

 made out. Yet on tke supposition of a solar ring reacking beyond tke eartk, 

 tke base of tkat kgkt must be 180,000,000 of miles from us, and tke vertex 

 comparatively only a very skort distance, wkile also tke wkole circuit of tke 

 ring is equally illuminated by tke sun, and tkose portions near our zenitk, as far 

 as I can judge, also more favorably situated for reflecting kis ligkt tkan tkose 

 portions at tke base. "We can scarcely imagine suck a state of tilings. 



Believing tkat tkis query must be answered in tke negative, I am driven to 

 tke only alternative of a nebulous ring around the earth. Tke moon's zodiacal 

 light seems also to show that matter lies within tke orbit of tke moon. I 

 skould judge from my observations tkat a cross section of tkis ring would be 

 pear shaped, allowing no inward curves to the pan- ; that its more condensed 

 or central portion is, as far as it shows itself to our eye, about 30 wide, while 

 the more diffuse will make an angle to the eye of 100. It appears to lie in 

 general along the ecliptic, except in December and June, wken observations 

 of several successive nights in both 1853 and 1854 seemed to indicate a cross- 

 ing of tke ecliptic line at an angle of 5 to 8 ; and perhaps, also, in Septem- 

 ber and March, a similar crossing in an opposite direction. We must 

 speak, however, with great distrust of its width, for we have only its reflec- 

 tion in the night, as its journey ings over the eye change its place with regard 

 to the ring itself, and thus bring different portions of its curved surface in a 

 position to produce reflection cognizant by the eye. Still, I think the dimen- 

 sions given above are near the truth. 



I do not come here, however, 'as the advocate of a theory, but to give you 

 tke possession of facts. And tke facts wkick I present are but meager com- 

 pared with what we need. I hope, if they do nothing more, tkat tkey will 

 increase tke number of observers on this interesting subject ; for it is not only 

 interesting in itself, but one of tke most striking tkiugs about it is tkat it is 

 suggestive. It leads tke mind far beyond itself. We may well query if tke 

 zodiacal ligkt comes from a nebulous ring around our eartk and witkin tke 

 orbit of the moon, may not the shooting stars and even the aerolites have 



