[Figures 39], [40], and [41] are the following sections of a tessaract.

Z X Y W
Z
O
.		X
I
.		Y
I
.		W
I		- 39is asectiontaken0.1⁄2.1⁄2.1⁄2
40„„„0.1.1.1
41„„„0.11⁄2.11⁄2.11⁄2

It is clear that there are four orders of sections of every four-dimensional figure; namely, those beginning with a solid, those beginning with a plane, those beginning with a line, and those beginning with a point. There should be little difficulty in finding them, if the sections of a cube with a tetra-hedron, or an octa-hedron enclosed in it, are carefully examined.

APPENDIX K.

Model 1. MALA.

Colours: Mala, Light-buff.

Points: Corvus, Gold. Nugæ, Fawn. Crus, Terra-cotta. Cista, Buff. Ilex, Light-blue. Sors, Dull-purple. Lama, Deep-blue. Olus, Red.