164 PROCEEDINGS OP THE AMERICAN ACADEMY 



appeared as it is some hours later. General impressions and, theories 

 upon the subject should be replaced by accurate observations. If the 

 sky grows sensibly darker for a long time after twilight, the zodiacal 

 light may of course become more apparent during this time. More- 

 over, the increase of sensitiveness in the observer's eye during the 

 evening may be more gradual than would at first be supposed. 



The next class of phenomena to be discussed is that comprising the 

 " zodiacal bands " reported by different observers. The wide zodiacal 

 band seen by Jones at Quito (Jq. 37 G) need not here be considered. 

 It is to be hoped that some equally enterprising observer will under- 

 take the re-examination of the subject under similarly favorable condi- 

 tions. At the present time, the Andes are occasionjflly visited by 

 amateur mountaineers who have exhausted the Alps, and perhaps they 

 will yet furnish us with a continuation of the interesting work wliich 

 Jones considered to be in itself a sufficient object for the joui-ney. 

 Although he thought that traces of the band he had seen at Quito 

 were afterwards perceptible from less advantageous stations (Jq. 378), 

 it is certain that very few observers have seen anything ap|)roa('hing 

 it in width, distinctness, and definite positiim in the zodiac ; and it is 

 still to be determmed whether it may not have been the effect of local 

 or temporary causes. 



The zodiacal bands more ordinarily seen have seldom been de- 

 scribed with the exactness requisite for making satisfactory compari- 

 sons between the reports of different observers. The account given 

 by Lewis (Ls. 441) resembles that given by Jones of his Quito obser- 

 vations in many important particulars. The additional facts furnished 

 by Lewis, that the band he saw was " more sharply defined on its 

 southern than on its northern edge," and that, " while its axis of .great- 

 est brightness is either on or very slightly north of the ecliptic, the 

 axis of symmetry is decidedly north of that line," apparently indicate 

 effects of atmospheric absorption. If these observations can be con- 

 firmed by others, they will have laid the foundation of an important 

 addition to our knowledixe. 



So far as I have learned, oidy one zodiacal band has been so repeat- 

 edly and definitely described as to leave no doubt of its existence. 

 This is a faint and narrow belt which takes a southwesterly course 

 from the Pleiades, or rather perhaps from a place on the southern 

 border of that group. In the Astronomische Nachrichten, XCIX. 

 91, 369, will be found a statement of some reasons for thinking that 

 this band should rather be considered as a branch of tlie Milky Way 

 than as especially zodiacal in its character. I am unable to trace it 



