Pale-yellow Livor Ovis k Purple-brown Opex Polus l Deep-crimson Camoena Pilum m Blue-green Proes Tergum n Light-brown Lua Crates o Deep-blue Lama Tyro p Brick-red Lar Cura q Magenta Offex Arvus r Green-grey Cadus Hama s Light-red Croeta Praeda t Azure Lotus Vitta u Pale-green Vesper Ocrea v Blue-tint Panax Telum w Yellow-green Pactum Malleus x Deep-green Mango Vomer y Light-green Lis Agmen z Light-blue Ilex Comes α Crimson Bolus Sypho β Ochre Limbus Mica γ Purple Solia Arcus δ Leaf-green Luca Securis ε Turquoise Ancilla Vinculum ζ Dark-grey Orca Colus η Fawn Nugæ Saltus θ Smoke Limus Sceptrum ι Light-buff Mala Pallor κ Dull-purple Sors Vestis λ Rich-red Lucta Cortex μ Green-blue Pator Flagellum ν Burnt-sienna Silex Luctus ξ Sea-blue Lorica Lacus ο Peacock-blue Passer Aries π Deep-brown Meatus Hydra ρ Dark-pink Onager Anguis σ Dark Lensa Laurus τ Dark-stone Pluvium Cudo υ Silver Spira Cervix φ Gold Corvus Urna χ Deep-yellow Via Spicula ψ Dark-green Calor Segmen ω APPENDIX E. A THEOREM IN FOUR-SPACE. If a pyramid on a triangular base be cut by a plane which passes through the three sides of the pyramid in such manner that the sides of the sectional triangle are not parallel to the corresponding sides of the triangle of the base; then the sides of these two triangles, if produced in pairs, will meet in three points which are in a straight line, namely, the line of intersection of the sectional plane and the plane of the base. Let A B C D be a pyramid on a triangular base A B C, and let a b c be a section such that A B, B C, A C, are respectively not parallel to a b, b c, a c. It must be understood that a is a point on A D, b is a point on B D, and c a point on C D. Let, A B and a b, produced, meet in m. B C and b c, produced, meet in n; and A C and a c, produced, meet in o. These three points, m, n, o, are in the line of intersection of the two planes A B C and a b c.