' |
| | | | m' | m' |
| xy | xy' | | .----|----. |
| | | | | xy | xy'| |
| | | | | m | m | |
|--------|--------| |---|----|----|---|
| | | | |x'y |x'y'| |
| | | | | m | m | |
| x'y | x'y' | | .----|----. |
| | | | x'y | x'y' |
| | | | m' | m' |
.-----------------. .-----------------.

CHAPTER I.

_SYMBOLS AND CELLS._

First, let us suppose that the above _left_-hand Diagram is the
Biliteral Diagram that we have been using in Book III., and that we
change it into a _Triliteral_ Diagram by drawing an _Inner Square_, so
as to divide each of its 4 Cells into 2 portions, thus making 8 Cells
altogether. The _right_-hand Diagram shows the result.

[The Reader is strongly advised, in reading this Chapter, _not_
to refer to the above Diagrams, but to make a large copy of the
right-hand one for himself, _without any letters_, and to have
it by him while he reads, and keep his finger on that particular
_part_ of it, about which he is reading.]
pg040
Secondly, let us suppose that we have selected a certain Adjunct, which
we may call "m", and have subdivided the xy-Class into the two Classes
whose Differentiae are m and m', and that we have assigned the N.W.
_Inner_ Cell to the one (which we may call "the Class of xym-Things", or
"the xym-Class"), and the N.W. _Outer_ Cell to the other (which we may
call "the Class of xym'-Things", or "the xym'-Class").

[Thus, in the "books" example, we might say "Let m mean 'bound',
so that m' will mean 'unbound'", and we might suppose that we
had subdivided the Class "old English books" into the two
Classes, "old English bound books" and "old English unbound
books", and had assigned the N.W. _Inner_ Cell to the one, and
the N.W. _Outer_ Cell to the other.]

Thirdly, let us suppose that we have subdivided the xy'-Class, the
x'y-Class, and the x'y'-Class in the same manner, and have, in each
case, assigned the _Inner_ Cell to the Class possessing the Attribute m,
and the _Outer_ Cell to the Class possessing the Attribute m'.

[Thus, in the "books" example, we might suppose that we had
subdivided the