Part 2 (1/2)

[Ill.u.s.tration: A globe.]

But because you shall not muse what I dooe call _a bound_, [Sidenote: A bounde.] I mean therby a generall name, betokening the beginning, end and side, of any forme.

[Sidenote: Forme, Fygure.] _A forme, figure, or shape_, is that thyng that is inclosed within one bond or manie bondes, so that you vnderstand that shape, that the eye doth discerne, and not the substance of the bodie.

Of _figures_ there be manie sortes, for either thei be made of p.r.i.c.kes, lines, or platte formes. Not withstandyng to speake properlie, _a figure_ is euer made by platte formes, and not of bare lines vnclosed, neither yet of p.r.i.c.kes.

Yet for the lighter forme of teachyng, it shall not be vnsemely to call all suche shapes, formes and figures, whiche y^e eye maie discerne distinctly.

And first to begin with p.r.i.c.kes, there maie be made diuerse formes of them, as partely here doeth folowe.

[Ill.u.s.tration: A lynearic numbre.

Trianguler numbres Longsquare nubre.

Iust square numbres a threcornered spire.

A square spire.]

And so maie there be infinite formes more, whiche I omitte for this time, csidering that their knowledg appertaineth more to Arithmetike figurall, than to Geometrie.

But yet one name of a p.r.i.c.ke, whiche he taketh rather of his place then of his fourme, maie I not ouerpa.s.se. And that is, when a p.r.i.c.ke standeth in the middell of a circle (as no circle can be made by cpa.s.se without it) then is it called _a centre_.

[Sidenote: A centre] And thereof doe masons, and other worke menne call that patron, a _centre_, whereby thei drawe the lines, for iust hewyng of stones for arches, vaultes, and chimneies, because the chefe vse of that patron is wrought by findyng that p.r.i.c.ke or centre, from whiche all the lynes are drawen, as in the thirde booke it doeth appere.

Lynes make diuerse figures also, though properly thei maie not be called figures, as I said before (vnles the lines do close) but onely for easie maner of teachyng, all shall be called figures, that the eye can discerne, of whiche this is one, when one line lyeth flatte (whiche is named [Sidenote: A ground line.] the _ground line_) and an other commeth downe on it, and is called [Sidenote: A perpendicular.] [Sidenote: A plume lyne.]

a _perpendiculer_ or _plume lyne_, as in this example you may see. where .A.B. is the grounde line, and C.D. the plumbe line.

[Ill.u.s.tration]

And like waies in this figure there are three lines, the grounde lyne whiche is A.B. the plumme line that is A.C. and the _bias line_, whiche goeth from the one of th? to the other, and lieth against the right corner in such a figure whiche is here .C.B.

[Ill.u.s.tration]

But consideryng that I shall haue occasion to declare sundry figures anon, I will first shew some certaine varietees of lines that close no figures, but are bare lynes, and of the other lines will I make mencion in the description of the figures.

[Ill.u.s.tration: tortuouse paralleles.]

[Sidenote: Parallelys]

[Sidenote: Gemowe lynes.]

_Paralleles_, or _gemowe lynes_ be suche lines as be drawen foorth still in one distaunce, and are no nerer in one place then in an other, for and if they be nerer at one ende then at the other, then are they no paralleles, but maie bee called _bought lynes_, and loe here exaumples of them bothe.

[Ill.u.s.tration: parallelis.]

[Ill.u.s.tration: bought lines]

[Ill.u.s.tration: parallelis: circular. Concentrikes.]

I haue added also _paralleles tortuouse_, whiche bowe ctrarie waies with their two endes: and _paralleles circular_, whiche be lyke vnperfecte compa.s.ses: for if they bee whole circles, [Sidenote: Concentrikes] then are they called _ccentrikes_, that is to saie, circles draw? on one centre.