re then a quarter,
that is D.E. Then do I set one foote of the compas vnaltered in
D, and stretch the other in the circular line, and it doth light
in F, this space betwene D. and F. I deuide into halfe in the
pricke G, whiche halfe I take with the compas, and set it beyond
F. vnto H, and thefore is H. the point, by whiche the
perpendicular line must be drawn, so say I that the line H.A, is
a plumbe line to A.B, as the conclusion would.

THE .VI. CONCLVSION.

To drawe a streight line from any pricke that is not in a
line, and to make it perpendicular to an other line.

Open your compas as so wide that it may extend somewhat farther,
then from the prick to the line, then sette the one foote of the
compas in the pricke, and with the other shall you draw a
compassed line, that shall crosse that other first line in .ij.
places. Now if you deuide that arch line into .ij. equall
partes, and from the middell pricke therof vnto the prick
without the line you drawe a streight line, it shalbe a plumbe
line to that firste lyne, accordyng to the conclusion.

[Illustration]

_Example._

C. is the appointed pricke, from whiche vnto the line A.B. I
must draw a perpendicular. Thefore I open the compas so wide, that
it may haue one foote in C, and thother to reach ouer the line,
and with y^t foote I draw an arch line as you see, betwene A.
and B, which arch line I deuide in the middell in the point D.
Then drawe I a line from C. to D, and it is perpendicular to the
line A.B, accordyng as my desire was.

THE .VII. CONCLVSION.

To make a plumbe lyne on any porcion of a circle, and that
on the vtter or inner bughte.

Mark first the prick where y^e plumbe line shal lyght: and prick
out of ech side of it .ij. other poinctes equally distant from
that first pricke. Then set the one foote of the compas in one of
those side prickes, and the other foote in the other side
pricke, and first moue one of the feete and drawe an arche line
ouer the middell pricke, then set the compas steddie with the
one foote in the other side pricke, and with the other foote
drawe an other arche line, that shall cut that first arche, and
from the very poincte of their meetyng, drawe a right line vnto
the firste pricke, where you do minde that the plumbe line shall
lyghte. And so haue you performed thintent of this conclusion.

_Example._

[Illustration]

The arche of the circle on whiche I would erect a plumbe line,
is A.B.C. and B