MR.. C4. UDNY YULE ON THE THEORY OF CONSISTENCE 
§18. Case (2). 
Pi = Pi 
The efRiatioiis to the Ijoundiiig planes 
= Pi ^ O'-i- 
are 
X — 
0 
y = 
0 z = 0. 
X “h 
y 
+ 
z = 
0-2 
(a) 
X + 
y 
— 
Z — 
0-4 
(/3) 
X — 
y 
+ 
Z =: 
0-4 
(r) 
— X 
y 
+ 
Z = 
0-4 
(8). 
The surface is shown in fig. 2a below, and in fig. 2b from a photograph of a model. 
The three edges ay, aS of the tetrahedron, that in fig. 1 lay in the co-ordinate 
planes, are now truncated hy tliem. Thus only three of the six infinite series of 
exact inferences occurring in the last case are left, viz., 
Given. 
X = 0'4 
IJ rrz 0-4 
z = 0’4 
Inferred. 
y = 2 
Z = X 
X = y. 
