5o 



Ellery W. Davis 



In the third place, and finally, it contains all the elements gotten 

 by referring the curve to all the possible pairs of conjugate 

 diameters as axes and then taking the totality of non-radial ele- 

 ments of the companion curves. 



The more general conic 



x 2 y 2, 

 ~ 2 +~ 2 = I 

 a b 



where a and b are non-similar complex quantities can be made to 

 depend on that just considered or more simply upon that of the 

 circle of complex radius. For any element is at once a vertical 

 projection of an element of 



* 2 + y 2 = a 2 



A & s 



It * v V u 



a 



;i ; / \ 



» // nsL/i\ 



HI \ W/ 



VVrW 



5° 



