OF ARTS AND SCIENCES. 



151 



TABLE I. 



cant, and makes no noticeable difference in the result for atmospheric 

 absorption. It will be seen that the observations of this group were 

 made in a more southern latitude than those of the next two groups, 

 and at about the same latitude as that in which the observations of the 

 fifth group were made. Meanwhile, the apparent shifting of the axis 

 follows the progressive, change of the inclination of the ecliptic, entirely 

 in accordance with the original theory of Jones. In order to form an 

 independent judgment upon the subject, the work of Serpieri must 

 be consulted, and the graphical arrangement of the observations, by 

 which he supports his argument, must be examined. My own con- 

 clusion is that the view taken by Jones was correct. 



All the evening observations of Heis and of Weber were made near 

 the fifty-second parallel of latitude, where the zodiacal light can only 

 be seen for the few months during which the zenith distance of the 

 north pole of the ecliptic is near its maximum at the time of observa- 

 tion. Under more favorable circumstances the fixed stations of these 

 observers would have aided us materially in distinguishing the cause 

 of the apparent movement of the zodiacal light in latitude. So far as 

 it goes, the evidence of Heis is in favor of a change due to an altered 

 position of the ecliptic, or rather to the resulting difference in atmos- 



