238 
ON THE BICIRCULAR QUARTIC. 
[667 
the exterior oval came out too large. The annexed figure shows 0, 1, 2, 3, the 
centres of the circles of inversion, the interior oval, and a portion of the exterior 
oval, also the origin and axes; it will be seen that the centres 0, 2 lie inside the 
interior oval, the centres 1, 3 outside the exterior oval: I add further the values 
Vf+ 03 = 6-93, V-(g + e 3 ) = 2-45, a a = 1018, & = - *98, 
V/+ 0, = 7-48, Vg + 0 1 
= 1-41, a 1 = 8-73, &= + 2-9 4, 
V/+ <9o = 7-75, Jg + 0 o 
vT+^“ = 8-94, 
= 2-45, a„= 815, /3 0 = + ‘98, 
= 5-09, a 2 = 610, & = + -23. 
We thus see how there exists a series of quadrilaterals ABGD, where A, B are 
situate on the interior oval, C, D on the exterior oval. Considering the sides as