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59

graph may be erased. The blot, it is true, fills
its whole area, so as to leave no room for
any other graph. But there is an equivalent
of it of which this is not true. For since by
the Permission No 1 every graph evenly on the sheet
of assertion enclosed[?] can be transformed into the blank,
it follows, by the principle of contraposition
that an enclosure containing
nothing but a blank can when evenly enclosed be transformed
into anything we please, and consequently
into the pseudograph. The vacant enclosure is, therefore,
a form of the pseudograph. For evenly
enclosed it can be transformed [into] the blot, or the
blot can be transformed into it. And since these