57

53

By combining the two parts of the definition
of the scroll we get the highly useful
graphical form of the principle of contraposition. Namely,
suppose that a replica of the graph x, were it scribed on the
sheet of assertion, would be permissively transformable
into a replica of the graph, y, and suppose
that the scroll

were permissively placed
on the sheet of assertion. Then, by the predication
of the definition concerning the definitum,
y, if scribed on the sheet of assertion,
would be transformable into z. So
x being transformable into y and y in its
turn into z, it follows that x would [on?] the

53

By combining the two parts of the definition
of the scroll we get the highly useful
graphical form of the principle of contraposition. Namely,
suppose that a replica of the graph x, were it scribed on the
sheet of assertion, would be permissively transformable
into a replica of the graph, y, and suppose
that the scroll \vscroll{y}{z}
were permissively placed
on the sheet of assertion. Then, by the predication
of the definition concerning the definitum,
y, if scribed on the sheet of assertion,
would be transformable into z. So
x being transformable into y and y in its
turn into z, it follows that x would [on?] the