322 Mr. J. H. Vincent on Models and Diagrams lo 

 When z = 2 we have the curves 2, 2. 



Section by Plane z=2. 



Inner 





Outer 





X. 



If- 



X. 



V- 



o-oo 



1-48 



0-00 



3-47 



0-50 



1-42 



0-50 



3-39 



1-00 



1*19 



1-00 



3-17 



111 



1-11 



1-23 



3-00 







1-53 



2-70 







1-96 



2-00 







1-98 



1-98 







2-00 



1-90 



1-25 



1-00 



2-21 



1-00 



1-53 



0-66 







1-61 



0-50 



2-24 



0-50 



1-73 



0-00 



2-24 



0-00 



The next section is taken through the singular points. The 

 curves are marked 2*58 ; the co-ordinates of a singular point 

 are 



y=o, 



2=2-58, 

 0=1-53. 



Section by Plane parallel lo XOY and through 

 the Singular Points. 



Inner. Outer. 



X. 



y- 



X. 



y> 



1-53 



o-oo 



1-53 



0-00 



1-20 



0-50 



1-72 



0-50 



1-00 



0-67 







081 



0-81 







0-50 



0-94 







0-26 



1-00 



1-74 



1-00 







1-64 



1-64 







1-52 



2-00 







1-00 



2-69 







0-50 



2-97 



0-00 



1-02 



0-00 



3-06 



If we put 2 = 3 in the equation to the surface we obtain the 

 curve marked 3. The section plane touches the inner surface 

 on the axis of z. It will be noticed that the projection of 

 this curve upon the XOY plane passes through the foci of the 



