334 SPECIAL RESULTS IN THE TJRANOLOGICAL 



Venus, the Earth, Saturn, and Uranus they are decreasing. 

 The following table gives the excentricities of the larger 

 planets according to Hansen for the year 1800 ; the excen- 

 tricities of the 14 small planets will be given subsequently, 

 together with the other elements of their orbits, for the 

 middle of the 19th century : 



Mercury .... 0-2056163 



Venus . . . ' . . 0-0068618 



Earth . . ,. . .' . 0-0167922 



Mars . ., . . . , ; ;. 0-0932168 



Jupiter . .. : ., . * 0-0481621 



Saturn ... 0-0561505 



Uranus ... 0-0466108 



Neptune . . . 0-0087195 



The movement of the major axis (line of the apsides) 

 in planetary orbits, whereby the place of the perihelion is 

 altered, takes place always in one direction. It is a change 

 in the position of the line of the apsides which would 

 require more than a hundred thousand years to complete its 

 cycle, and is to be thoroughly distinguished from the 

 changes of form or of ellipticity suffered by the orbits. The 

 question has been mooted whether, in the course of several 

 thousand years, the increasing value of this element could 

 modify in a considerable degree the temperature of the 

 Earth, in respect to its amount and distribution in the 

 different parts of the day and of the year? Whether 

 there might not be found in these regularly and continually 

 acting astronomical causes a partial solution of the great geo- 

 logical problem of the remains of tropical vegetable and ani- 

 mal forms in the present cold zone ? The same mathematical 



