4

4

fundamental alpha permissible operations. Namely
of these six, there are three that complicate the
graph and three that simplify it. The three that
complicate is are insertion, iteration and the [?] making
of a double [?]. The three that simplify it are erasure,
reiteration, and the cancelling of a double [cut?]. These [?]
these are the six operations, [the/two?] only that are not re-
visible, that is which can not may not be undone as well
as done. These are erasure and insertion. Now my
idea in drawling up the rule, in the first place to
to define to myself precisely on [?] what occasion the complicating one-
[?] might be indispensable in ascertaining
whether a graph was possible or not, and to restrict
their virtual employment to these cases, and in the
second place, so to modify the non-revisable operations

fundamental alpha permissible operations. Namely
of these six, there are three that complicate the
graph and three that simplify it. The three that
complicate is are insertion, iteration and the [?] making
of a double [?]. The three that simplify it are erasure,
reiteration, and the cancelling of a double [cut?]. These [?]
these are the six operations, [the/two?] only that are not re-
visible, that is which can not may not be undone as well
as done. These are erasure and insertion. Now my
idea in drawling up the rule, in the first place to
to define to myself precisely on [?] what occasion the complicating one-
[?] might be indispensable in ascertaining
whether a graph was possible or not, and to restrict
their virtual employment to these cases, and in the
second place, so to modify the non-revisable operations