where thei two do crosse, thense draw
a line to the poinct where you woulde haue the perpendicular
line to light, and you haue doone.

_Example._

[Illustration]

The line is A.B. and A. is the prick, on whiche the
perpendicular line must light. Therfore I deuide A.B. into fiue
partes equall, then do I open the compas to the widenesse of
three partes (that is A.D.) and let one foote staie in A. and
with the other I make an arche line in C. Afterwarde I open the
compas as wide as A.B. (that is as wide as all fiue partes) and
set one foote in the .iiij. pricke, which is E, drawyng an arch
line with the other foote in C. also. Then do I draw thence a
line vnto A, and so haue I doone. But and if the line be to
shorte to be parted into fiue partes, I shall deuide it into
iij. partes only, as you see the liue F.G, and then make D. an
other line (as is K.L.) whiche I deuide into .v. suche
diuisions, as F.G. containeth .iij, then open I the compass as
wide as .iiij. partes (whiche is K.M.) and so set I one foote of
the compas in F, and with the other I drawe an arch lyne toward
H, then open I the compas as wide as K.L. (that is all .v.
partes) and set one foote in G, (that is the iij. pricke) and
with the other I draw an arch line toward H. also: and where
those .ij. arch lines do crosse (whiche is by H.) thence draw I
a line vnto F, and that maketh a very plumbe line to F.G, as my
desire was. The maner of workyng of this conclusion, is like to
the second conlusion, but the reason of it doth depend of the
.xlvi. proposicion of y^e first boke of Euclide. An other waie
yet. set one foote of the compas in the prick, on whiche you
would haue the plumbe line to light, and stretche forth thother
foote toward the longest end of the line, as wide as you can for
the length of the line, and so draw a quarter of a compas or
more, then without stirryng of the compas, set one foote of it
in the same line, where as the circular line did begin, and
extend thother in the circular line, settyng a marke where it
doth light, then take half that quantitie more there vnto, and
by that prick that endeth the last part, draw a line to the
pricke assigned, and it shall be a perpendicular.

[Illustration]

_Example._

A.B. is the line appointed, to whiche I must make a
perpendicular line to light in the pricke assigned, which is A.
Therfore doo I set one foote of the compas in A, and extend the
other vnto D. makyng a part of a circle, mo