THE DEFINITIONS OF THE PRINCIPLES OF GEOMETRY . (RECORD-E1-P1,1,A1R.3) Geometry teacheth the drawyng , Measuring and proporcion of figures , (RECORD-E1-P1,1,A1R.5) but in as muche as no figure can be drawen , but it muste haue certayne bou~des and inclosures of lines : and euery lyne also is begon and ended at some certaine prycke , fyrst it shall be meete to know these smaller partes of euery figure , that therby the whole figures may the better bee iudged , and distincte in sonder . (RECORD-E1-P1,1,A1R.6) A Poynt or a Prycke , is named of Geometricans that small and vnsensible shape , which hath in it no partes , that is to say : nother length , breadth nor depth . (RECORD-E1-P1,1,A1R.7) But as this exactnes of definition is more meeter for onlye Theorike speculacion , then for practise and outwarde worke consideringe that myne intente is to applye all these whole principles to woork I thynke meeter for this purpose , to call a poynt or prycke , that small printe of penne , pencyle , or other instrumente , which is not moued , nor drawen from his fyrst touche , and therfore hath no notable length nor bredthe : as this example doeth declare . {COM:three_points_omitted} Where I haue set .iij. prickes , eche of them hauyng both le~gth and bredth , thogh it be but smal , and therfore not notable (RECORD-E1-P1,1,A1R.8) Nowe of a great numbre of these prickes , is made a Lyne , as you may perceiue by this forme ensuyng . {COM:series_of_points_omitted} where as I haue set a number of prickes , so if you with your pen will set in more other prickes betweene euerye two of these , then wil it be a lyne , as here you may see (RECORD-E1-P1,1,A1R.9) {COM:line_omitted} and this lyne , is called of Geometricians , Lengthe withoute breadth . (RECORD-E1-P1,1,A1R.11) But as they in theyr theorikes which ar only mind workes do precisely vnderstand these definitions , so it shal be sufficient for those men , whiche seke the vse of the same thinges , as sense may duely iudge them , and applye to handy workes if they vnderstand them so to be true , that outwarde sense canne fynde none erroure therin . (RECORD-E1-P1,1,A1V.12) Of lynes there bee two principall kyndes . (RECORD-E1-P1,1,A1V.13) The one is called a right or straight lyne , and the other a croked lyne . (RECORD-E1-P1,1,A1V.14) A straight lyne , is the shortest that maye be drawenne betweene two prickes . (RECORD-E1-P1,1,A1V.15) And all other lines , that go not right forth from prick to prick , but boweth any waye , such are called Croke lynes as in these examples folowyng ye may se , where I haue set but one forme of a straight lyne , (RECORD-E1-P1,1,A1V.16) for more formes there be not , (RECORD-E1-P1,1,A1V.17) but of crooked lynes there bee innumerable diuersities , whereof for examples sum I haue sette here . (RECORD-E1-P1,1,A1V.18) A right lyne . (RECORD-E1-P1,1,A1V.19) Croked lines . (RECORD-E1-P1,1,A1V.20) {COM:figures_omitted} So now you must vnderstand , that euery lyne is drawen betwene twoo prickes , wherof the one is at the beginning , and the other at the ende . (RECORD-E1-P1,1,A1V.22) Therfore when soeuer you do see any formes of lynes to touche at one notable pricke , as in this example , then shall you not call it one croked lyne , but rather twoo lynes : in as muche as there is a notable and sensible angle by .A. whiche euermore is made by the meetyng of two seuerall lynes . (RECORD-E1-P1,1,A2R.23) And likewayes shall you iudge of this figure , which is made of two lines , and not of one onely . So that whan so euer any suche meetyng of lines doth happen , the place of their metyng is called an Angle or corner . (RECORD-E1-P1,1,A2R.24) Of angles there be three generall kindes : a sharpe angle , a square angle , and a blunte angle . (RECORD-E1-P1,1,A2R.25) The square angle , whiche is commonly named a right corner , is made of twoo lynes meetyng together in fourme of a squire , which two lines , if they be drawen forth in length , will cross one an other : as in the examples folowyng you maie see . (RECORD-E1-P1,1,A2R.26) A sharpe angle is so called , because it is lesser than is a square angle , and the lines that make it , do not open so wide in their departynge as in a square corner , (RECORD-E1-P1,1,A2R.27) and if thei be drawen crosse , all fower corners will not be equall . (RECORD-E1-P1,1,A2R.28) A blunt or brode corner , is greater then is a square angle , (RECORD-E1-P1,1,A2R.29) and his lines do parte more in sonder then in a right angle , of which all take these examples . (RECORD-E1-P1,1,A2R.30) Right angles . (RECORD-E1-P1,1,A2R.32) Sharpe angles . (RECORD-E1-P1,1,A2R.33) {COM:figures_omitted} And these angles as you see are made partly of streght lynes , partly of croked lines , and partly of both together . (RECORD-E1-P1,1,A2R.36) Howbeit in right angles I haue put none example of croked lines , because it would muche trouble a lerner to iudge them : (RECORD-E1-P1,1,A2V.37) for their true iudgement doth appertaine to arte perspectiue , and as I may say , rather to reason then to sense . (RECORD-E1-P1,1,A2V.38) Blunte or brode angles . (RECORD-E1-P1,1,A2V.40) {COM:figures_omitted} But now as of many prickes there is made one line , so of diuerse lines are there made sundry formes , figures , and shapes , which all yet be called by one propre name , Platte formes , (RECORD-E1-P1,1,A2V.43) and thei haue bothe length and bredth , but yet no depenesse . (RECORD-E1-P1,1,A2V.44) And the boundes of euerie platte forme are lines : as by the examples you maie perceiue . (RECORD-E1-P1,1,A2V.45) Of platte formes some be plain , and some be croked , and some partly plaine , and partlie croked . (RECORD-E1-P1,1,A2V.46) A plaine platte is that , which is made al equall in height , so that the middle partes nother bulke vp , nother shrink down more then the both endes . (RECORD-E1-P1,1,A2V.47) For whan the one parte is higher then the other , then is it named a Croked platte . (RECORD-E1-P1,1,A2V.48) And if it be partlie plaine , and partlie crooked , then is it called a Myxte platte , of all whiche , these are exaumples . (RECORD-E1-P1,1,A2V.49) A plaine platte . (RECORD-E1-P1,1,A2V.51) A croked platte . (RECORD-E1-P1,1,A2V.52) A myxte platte . (RECORD-E1-P1,1,A2V.53) And as of many prickes is made a line , and of diuerse lines one platte forme , so of manie plattes is made a bodie which conteighneth Lengthe , bredth , and depenesse . (RECORD-E1-P1,1,A2V.55) By Depenesse I vnderstand , not as the common sort doth , the holownesse of anything , as of a well , a diche , a potte , and suche like , (RECORD-E1-P1,1,A2V.56) but I meane the massie thickness of any bodie , as in exaumple of a potte : the depenesse is after the common name , the space from his brimme to his bottome . (RECORD-E1-P1,1,A3R.57) But as I take it here , the depenesse of his bodie is his thicknesse in the sides , which is an other thyng cleane different from the depenesse of his holownes , that the common people meaneth . (RECORD-E1-P1,1,A3R.58) Now all bodies haue platte formes for their boundes , (RECORD-E1-P1,1,A3R.59) so in a dye which is called a cubike bodie by geometricians , and an ashler of masons , there are .vi. sides , which are .vi. platte formes , and are the boundes of the dye . (RECORD-E1-P1,1,A3R.60) But in a Globe , which is a bodie rounde as a bowle there is but one platte forme , and one bounde , (RECORD-E1-P1,1,A3R.61) and these are the exaumples of them bothe . (RECORD-E1-P1,1,A3R.62) A dye or ashler . (RECORD-E1-P1,1,A3R.64) A globe . (RECORD-E1-P1,1,A3R.65) {COM:figures_omitted} But because you shall not muse what I dooe call a bound , I mean thereby a generall name , betokening the beginning , end and side , of any forme . (RECORD-E1-P1,1,A3R.68) A forme , figure , or shape , is that thyng that is inclosed within one bond or many bondes , so that you vnderstand that shape , that the eye doth discerne , and not the substance of the bodie . (RECORD-E1-P1,1,A3R.69) Of figures there be manie sortes , (RECORD-E1-P1,1,A3R.70) for either thei be made of prickes , lines , or platte formes . (RECORD-E1-P1,1,A3R.71) Notwithstandyng to speake properlie , a figure is euer made by platte formes , and not of bare lines vnclosed , neither yet of prickes . (RECORD-E1-P1,1,A3R.72) 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 . (RECORD-E1-P1,1,A3R.73) And first to begin with prickes , there maie be made diuerse formes of them , as partely here doeth folowe . (RECORD-E1-P1,1,A3R.74) A lynearie number . (RECORD-E1-P1,1,A3V.77) Trianguler numbres (RECORD-E1-P1,1,A3V.78) Long square nu~bre (RECORD-E1-P1,1,A3V.79) Iust square numbers (RECORD-E1-P1,1,A3V.80) a threcornered spire . (RECORD-E1-P1,1,A3V.81) A square spire . (RECORD-E1-P1,1,A3V.82) {COM:figures_omitted} And so maie there be infinite formes more , whiche I omitte for this time , co~sidering that their knowledg appertaineth more to Arithmetike figurall , than to Geometrie . (RECORD-E1-P1,1,A3V.85) But yet one name of the pricke , whiche he taketh rather of his place then of his fourme , maie I not ouerpasse . (RECORD-E1-P1,1,A3V.86) And that is , when a pricke standeth in the middell of a circle as no circle can be made by co~passe without it then is it called a centre . (RECORD-E1-P1,1,A3V.87) And thereof doe masons , and other worke menne call that patron , a centre , whereby they 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 pricke or centre , from whiche all the lynes are drawen , as in the thirde booke it doeth appere . (RECORD-E1-P1,1,A3V.88) Lynes make diuerse figures also , though properly thei maie not be called figures , as I said before vnles the lines do close (RECORD-E1-P1,1,A3V.89) 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 the ground line and an other commeth downe on it , and is called a perpendiculer or plu~me lyne , as in this example you may see , where .A.B. is the grounde line , and C.D. the plumbe line . (RECORD-E1-P1,1,A4R.90) {COM:figure_omitted} And likewaies 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 the~ to the other , and lieth against the right corner in such a figure whiche is here .C.B. (RECORD-E1-P1,1,A4R.92) {COM:figure_omitted} But consideryng that I shall haue occasion to declare sundry figures anon , I will first shew some certain varietees of lines that close no figures , but are bare lines , (RECORD-E1-P1,1,A4R.94) and of the other lines will I make mencion in the description of the figures . (RECORD-E1-P1,1,A4R.95) Paralleles , or gemowe lynes be such lines as be drawen foorth still in one distaunce , and are not nerer in one place then in an other , (RECORD-E1-P1,1,A4R.96) for and if they be nerer at one ende then at the other , then are they no parallels , (RECORD-E1-P1,1,A4R.97) but maie bee called bought lynes (RECORD-E1-P1,1,A4R.98) and soe here exaumples of the bothe . (RECORD-E1-P1,1,A4R.99) tortuouse paralleles . (RECORD-E1-P1,1,A4R.101) {COM:figure_omitted} parallelis . (RECORD-E1-P1,1,A4V.106) bought lines (RECORD-E1-P1,1,A4V.107) parallelis circular : (RECORD-E1-P1,1,A4V.108) Concentrikes . (RECORD-E1-P1,1,A4V.109) {COM:figures_omitted} I haue added also paralleles tortuouse , which bowe co~trarie waies with their two endes : and paralleles circular , which be lyke vnperfecte compasses : (RECORD-E1-P1,1,A4V.112) for if they bee whole circles , then are they called co~centrikes , (RECORD-E1-P1,1,A4V.113) that is to saie , circles drawe~ on one centre . (RECORD-E1-P1,1,A4V.114) Here might I note the error of good Albert Durer , which affirmeth that no perpendicular lines can be paralleles , which errour doeth spring partlie of ouersight of the difference of a streight line , and partlie of mistakyng certain principles geometrical , which al I wil let passe vntil an other tyme , and wil not blame him , which hath deserued worthyly infinite praise . (RECORD-E1-P1,1,A4V.115) And to returne to my matter . (RECORD-E1-P1,1,A4V.116) an other fashioned line is there , which is named a twine or twist line , (RECORD-E1-P1,1,A4V.117) and it goeth as a wreyth about some other bodie . (RECORD-E1-P1,1,A4V.118) And an other sorte of lines is there , that is called a spirall line , or a worm line , whiche representeth an apparant forme of many circles , where there is not one in dede : (RECORD-E1-P1,1,A4V.119) of these .ii. kindes of lines , these be examples . (RECORD-E1-P1,1,A4V.120) A twiste lyne . (RECORD-E1-P1,1,A4V.122) A spirail lyne (RECORD-E1-P1,1,A4V.123) {COM:figures_omitted} {COM:insert_helsinki_sample_1_here} THE .VII. CONCLVSION . (RECORD-E1-P1,1,C4V.129) TO MAKE A PLUMBE LYNE OR ANY PORCION OF A CIRCLE , (RECORD-E1-P1,1,C4V.132) AND THAT ON THE VTTER OR INNER BUGHTE . (RECORD-E1-P1,1,C4V.133) Mark first the pricke where y=e= plu~mbe line shal lyght : (RECORD-E1-P1,1,C4V.135) and prick out on each side of it .ij. other poinctes equally distant from that first pricke . (RECORD-E1-P1,1,C4V.136) Then set the one foote of the co~pas in one of those side prickes , and the other foote in the other side pricke , (RECORD-E1-P1,1,C4V.137) and first moue one of the feete (RECORD-E1-P1,1,C4V.138) and drawe an arche line ouer the middell pricke , (RECORD-E1-P1,1,C4V.139) then set the compas steddie with the one foote in the other side pricke , (RECORD-E1-P1,1,C4V.140) and with the other foote drawe an other arche line , that shall cut that first arche , (RECORD-E1-P1,1,C4V.141) and from the very poincte of the meetyng , drawe a right line vnto the firste pricke , where you do minde that the plumbe line shall lyghte . (RECORD-E1-P1,1,C4V.142) And so haue you performed thintent of this conclusion . (RECORD-E1-P1,1,C4V.143) Example . (RECORD-E1-P1,1,C4V.145) {COM:figure_omitted} The arche of the circle on whiche I would erect a plumbe line , is A.B.C . (RECORD-E1-P1,1,C4V.148) and B. is the pricke where I would haue the plumbe line to light . (RECORD-E1-P1,1,C4V.149) Therfore I meate out two equall distaunces on eache side of that pricke B . (RECORD-E1-P1,1,C4V.150) and they are A. C . (RECORD-E1-P1,1,C4V.151) Then open I the compas as wide as A.C . (RECORD-E1-P1,1,C4V.152) and settyng one of the feete in A. with the other I drawe an arch line which goeth by G . (RECORD-E1-P1,1,C4V.153) Likewaies I set one foote of the compas steddily in C . (RECORD-E1-P1,1,C4V.154) and with the other I draw an arche line , goyng by G. also . (RECORD-E1-P1,1,C4V.155) Now consideryng that G. is the pricke of their meetyng , it shall be also the poinct from whiche I must drawe the plu~be line . (RECORD-E1-P1,1,C4V.156) Then draw I a right line from G. to B. (RECORD-E1-P1,1,C4V.157) and so haue mine intent . (RECORD-E1-P1,1,C4V.158) Now as A.B.C. hath a plumbe line erected on his vtter bought , so may I erect a plumbe line on the inner $bught of D.E.F , doynge with it as I did with the other , (RECORD-E1-P1,1,D1R.159) that is to saye , fyrste settyng forthe the pricke where the plumbe line shall light , which is E , and then markyng one other on eache syde , as are D. and F . And then proceding as I dyd in the example before . (RECORD-E1-P1,1,D1R.160) THE VIII. CONCLVSION . (RECORD-E1-P1,1,D1R.162) HOW TO DEUIDE THE ARCHE OF A CIRCLE INTO TWO =L PARTES , WITHOUT MEASURING THE ARCHE . (RECORD-E1-P1,1,D1R.165) Deuide the corde of that line into ij. equall portions , (RECORD-E1-P1,1,D1R.167) and then from the middle prycke erecte a plumbe line , (RECORD-E1-P1,1,D1R.168) and it shal parte that arche in the middle . (RECORD-E1-P1,1,D1R.169) Example . (RECORD-E1-P1,1,D1R.171) {COM:figure_omitted} The arch to be diuided ys A.D.C , (RECORD-E1-P1,1,D1R.174) the corde is A,B.C {COM:sic} , (RECORD-E1-P1,1,D1R.175) this corde is diuided in the middle with B , from which prick if I erecte a plumb line as B.D , the~ will it diuide the arch in the middle , that is to say , in D . (RECORD-E1-P1,1,D1R.176) THE IX. CONCLVSION . (RECORD-E1-P1,1,D1R.178) To do the same thynge other wise . (RECORD-E1-P1,1,D1R.180) And for shortenes of worke , if you wyl make a plumbe line without much labour , you may do it with your squyre , so that it be iustly made , (RECORD-E1-P1,1,D1R.181) for yf you applye the edge of the squyre to the line in which the pricke is , and foresee the very corner of the squyre doo touche the pricke . And than frome that corner if you drawe a lyne by the other edge of the squyre , yt will be a perpendicular to the former line . (RECORD-E1-P1,1,D1R.182) Example . (RECORD-E1-P1,1,D1V.185) {COM:figure_omitted} A.B. is the line , on which I would make the plumme line , or perpendicular . (RECORD-E1-P1,1,D1V.188) And therefore I marke the prick , from which the plumbe lyne muste rise , which here is C . (RECORD-E1-P1,1,D1V.189) Then do I sette one edg of my squyre that is B.C. to the line A.B , so that the corner of the squyre do touche C. iustly . (RECORD-E1-P1,1,D1V.190) And from C. I drawe a line by the other edge of the squire , which is C.D . (RECORD-E1-P1,1,D1V.191) And so haue I made the plumme line D.C , which I sought for . (RECORD-E1-P1,1,D1V.192) THE X. CONCLVSION . (RECORD-E1-P1,1,D1V.194) HOW TO DO THE SAME THINGE AN OTHER WAY YET (RECORD-E1-P1,1,D1V.197) If so be it that you haue an arche of such greatnes , that your squyre wyll not suffice therto , as the arche of a brydge or of a house or window , then may you do this . (RECORD-E1-P1,1,D1V.199) Mete vnderneth the arch where y=e= midle of his cord wyl be , (RECORD-E1-P1,1,D1V.200) and there set a mark (RECORD-E1-P1,1,D1V.201) Then take a long line with a plummet , (RECORD-E1-P1,1,D1V.202) and holde the line in such a place of the arch that the plummet do hang iustely ouer the middle of the corde , that you didde diuide before , (RECORD-E1-P1,1,D1V.203) and then the line doth shewe you the middle of the arche . (RECORD-E1-P1,1,D1V.204) Example . (RECORD-E1-P1,1,D1V.206) {COM:figure_omitted} The arch is A.D.B , of which I trye the midle thus . (RECORD-E1-P1,1,D1V.209) I draw a corde from one syde to the other as here is A.B , which I diuide in the middle in C . (RECORD-E1-P1,1,D1V.210) The~ take I a line with a plummet that is D.E , (RECORD-E1-P1,1,D1V.211) and so hold I the line that the plummet B , dooth hange ouer C , (RECORD-E1-P1,1,D1V.212) And then I say that D. is the middle of the arche . (RECORD-E1-P1,1,D2R.213) And to thentent that my plummet shall point the more iustely , I doo make it sharpe at the nether ende , (RECORD-E1-P1,1,D2R.214) and so may I trust this woorke for certaine . (RECORD-E1-P1,1,D2R.215) THE XI. CONCLVSION . (RECORD-E1-P1,1,D2R.217) WHEN ANY LINE IS APPOINTED AND WITHOUT IT A PRICKE , WHEREBY A PARALLEL MUST BE DRAWEN HOW YOU SHALL DOO IT . (RECORD-E1-P1,1,D2R.220) Take the iuste measure betweene the line and the pricke , accordinge to which you shal open your compasse . (RECORD-E1-P1,1,D2R.222) The~ pitch one foote of your compasse at the one ende of the line , (RECORD-E1-P1,1,D2R.223) and with the other foote draw a bowe line right ouer the pytche of the compasse , (RECORD-E1-P1,1,D2R.224) lykewise doo at the other ende of the lyne , (RECORD-E1-P1,1,D2R.225) then draw a line that shall touche the vttermoste edge of bothe those bowe lines , (RECORD-E1-P1,1,D2R.226) and it will bee a true parallele to the fyrste lyne appointed . (RECORD-E1-P1,1,D2R.227) Example . (RECORD-E1-P1,1,D2R.229) {COM:figure_omitted} A.B , is the line vnto which I must draw an other gemowe line , which must passe by the prick C , (RECORD-E1-P1,1,D2R.232) first I meate with my compasse the smallest distance that is from C. to the line , (RECORD-E1-P1,1,D2R.233) and that is C.F , wherfore staying the compasse at that distaunce , I sette the one foote in A , (RECORD-E1-P1,1,D2R.234) and with the other foot I make a bowe lyne , which is D , (RECORD-E1-P1,1,D2R.235) the~ like wise set I the one foote of the compasse in B , (RECORD-E1-P1,1,D2R.236) and with the other I make the second bow line , which is E . (RECORD-E1-P1,1,D2R.237) And then draw I a line , so that it toucheth the vttermost edge of bothe these bowe lines , (RECORD-E1-P1,1,D2R.238) and that lyne passeth by the pricke C , (RECORD-E1-P1,1,D2R.239) and is a gemowe line to A.B , as my sekyng was . (RECORD-E1-P1,1,D2R.240) THE .XII. CONCLVSION . (RECORD-E1-P1,1,D2V.243) TO MAKE A TRIANGLE OF ANY .III. LINES , SO THAT THE LINES BE SUCHE , THAT ANY .IJ. OF THEM BE LONGER THEN THE THIRDE . (RECORD-E1-P1,1,D2V.246) FOR THIS RULE IS GENERALL , THAT ANY TWO SIDES OF EUERIE TRIANGLE TAKEN TOGETHER , ARE LONGER THEN THE OTHER SIDE THAT REMAINETH . (RECORD-E1-P1,1,D2V.247) If you do remember the first and seconde conclusions , then is there no difficultie in this , (RECORD-E1-P1,1,D2V.249) for it in maner the same woorke . (RECORD-E1-P1,1,D2V.250) First co~sider the .iij. lines that you must take , (RECORD-E1-P1,1,D2V.251) and set one of the~ for the ground line , (RECORD-E1-P1,1,D2V.252) then worke with the other .ij. lines as you did in the first and second conclusions . (RECORD-E1-P1,1,D2V.253) Example . (RECORD-E1-P1,1,D2V.255) {COM:figure_omitted} I haue .iij. lynes .A.B. and C.D. and E.F. of which I put .C.D. for my ground line , (RECORD-E1-P1,1,D2V.258) then with my compas I take the length of .A.B. , (RECORD-E1-P1,1,D2V.259) and set the one foote of my compas in C , (RECORD-E1-P1,1,D2V.260) and draw an archline with the other foote . (RECORD-E1-P1,1,D2V.261) Likewaies I take the le~gth of E.F , (RECORD-E1-P1,1,D2V.262) and set one foote in D , (RECORD-E1-P1,1,D2V.263) and with the other foote I make an arch line crosse the other arche , (RECORD-E1-P1,1,D2V.264) and the pricke of their metyng whiche is G. shall be the thirde corner of the triangle , (RECORD-E1-P1,1,D2V.265) for in all such kyndes of woorkynge to make a tryangle , if you haue one line drawen , there remayneth nothyng els but to fynde where the pitche of the thirde corner shal bee , (RECORD-E1-P1,1,D2V.266) for two of them must needes be at the two eandes of the lyne that is drawen . (RECORD-E1-P1,1,D2V.267) THE XIII. CONCLVSION . (RECORD-E1-P1,1,D3R.270) IF YOU HAUE A LINE APPOINTED , AND A POINTE IN IT LIMITED , HOWE YOU MAYE MAKE ON IT A RIGHTE LINED ANGLE , =LY TO AN OTHER RIGHT LINED ANGLE , ALLREADY ASSIGNED . (RECORD-E1-P1,1,D3R.273) Fyrste draw a line against the corner assigned , (RECORD-E1-P1,1,D3R.275) and so is it a triangle , (RECORD-E1-P1,1,D3R.276) then take heede to the line and the pointe in it assigned , (RECORD-E1-P1,1,D3R.277) and consider if that line from the pricke to this end bee as long as any of the sides that make the triangle assigned , (RECORD-E1-P1,1,D3R.278) and if it bee longe inoughe , then prick out there the length of one of the lines , (RECORD-E1-P1,1,D3R.279) and then woorke with the other two lines , accordinge to the laste conclusion , makynge a triangle of thre like lynes to that assigned triangle . (RECORD-E1-P1,1,D3R.280) If it bee not longe inoughe , thenne lengthen it fyrste , (RECORD-E1-P1,1,D3R.281) and afterwarde doo as I haue sayde before . (RECORD-E1-P1,1,D3R.282) Example . (RECORD-E1-P1,1,D3R.284) {COM:figure_omitted} Lette the angle appoynted bee A.B.C , and the corner assigned , B . (RECORD-E1-P1,1,D3R.287) Farthermore let the lymited line bee D.G , and the pricke assigned D . (RECORD-E1-P1,1,D3R.288) Fyrste therefore by drawinge the line A.C , I make the triangle A.B.C . (RECORD-E1-P1,1,D3R.289) Then consideringe that D.G , is longer thanne A.B , you shall cut out a line fro~ D toward G , equal to A.B , as for exa~ple D,F . (RECORD-E1-P1,1,D3R.290) The~ measure oute the other ij. lines (RECORD-E1-P1,1,D3R.291) and worke with the~ according as the conclusion with the fyrste also and the second teacheth yow , (RECORD-E1-P1,1,D3R.292) and then haue you done . (RECORD-E1-P1,1,D3R.293) THE XIIII. CONCLVSION . (RECORD-E1-P1,1,D3V.296) TO MAKE A SQUARE QUADRATE OF ANY RIGHTE LYNE APPOINCTED . (RECORD-E1-P1,1,D3V.299) First make a plumbe line vnto your line apointed , whiche shall light at one of the endes of it , accordyng to the fifth conclusion , (RECORD-E1-P1,1,D3V.301) and let it be of like length as your first line is , (RECORD-E1-P1,1,D3V.302) then ope~ your compasse to the iuste length of one of them , (RECORD-E1-P1,1,D3V.303) and sette one foote of the compasse in the ende of the one line , (RECORD-E1-P1,1,D3V.304) and with the other foote draw an arche line , there as you thinke that the fowerth corner shall be , (RECORD-E1-P1,1,D3V.305) after that set the one foote of the same compasse vnsturred , in the eande of the other line , (RECORD-E1-P1,1,D3V.306) and draw an other arche line crosse the first arche line , (RECORD-E1-P1,1,D3V.307) and the poincte that they do crosse in , is the pricke of the fourth corner of the square quadrate which you seke for , (RECORD-E1-P1,1,D3V.308) therfore draw a line from that pricke to the eande of eche line , (RECORD-E1-P1,1,D3V.309) and you shall therby haue made a square quadrate . (RECORD-E1-P1,1,D3V.310) Example . (RECORD-E1-P1,1,D3V.312) {COM:figure_omitted} A.B. is the line proposed , of whiche I shall make a square quadrate , (RECORD-E1-P1,1,D3V.315) therefore firste I make a plu~be line vnto it , which shall lighte in A , and the plu~b line in A.C , (RECORD-E1-P1,1,D3V.316) then open I my compasse as wide as the length of A.B , or A.C , (RECORD-E1-P1,1,D3V.317) for they must be bothe equall (RECORD-E1-P1,1,D3V.318) and I set the one foote of thend in C , (RECORD-E1-P1,1,D3V.319) and with the other I make an arche line nigh vnto D , (RECORD-E1-P1,1,D3V.320) afterward I set the compas again with one foote in B , (RECORD-E1-P1,1,D3V.321) and with the other foote I make an arche line crosse the first arche line in D , (RECORD-E1-P1,1,D3V.322) and from the prick of their crossyng I draw .ij. lines , one to B , and an other to C , (RECORD-E1-P1,1,D3V.323) and so haue I made the square quadrate that I entended . (RECORD-E1-P1,1,D3V.324) THE .XV. CONCLVSION . (RECORD-E1-P1,1,D4R.327) TO MAKE A LIKEIA~ME =L TO A TRIANGLE APPOINTED , (RECORD-E1-P1,1,D4R.330) AND THAT IN A RIGHT LINED A~GLE LIMITED . (RECORD-E1-P1,1,D4R.331) First from one of the angles of the triangle , you shall draw a gemowe line , whiche shall be a parallel to that syde of the triangle , on whiche you will make that likeiamme . (RECORD-E1-P1,1,D4R.333) Then on one end of the side of the triangle , whiche lieth against the gemowe lyne , you shall draw forth a line vnto the gemow line , so that one angle that commeth of those .ij. lines be like to the angle whiche is limited vnto you . (RECORD-E1-P1,1,D4R.334) Then shall you deuide into ij. equall partes that side of the triangle whiche beareth that line , (RECORD-E1-P1,1,D4R.335) and from the pricke of that deuision , you shall raise an other line parallele to that former line , and continewe it vnto the first gemowe line , (RECORD-E1-P1,1,D4R.336) and the~ of those .ij. last gemowe lyndes , and the first gemowe line , with the halfe side of the triangle , is made a lykeiamme equally to the triangle appointed , (RECORD-E1-P1,1,D4R.337) and hath an angle lyke to an angle limited , accordyng vnto the conclusion . (RECORD-E1-P1,1,D4R.338) Example . (RECORD-E1-P1,1,D4R.340) {COM:figure_omitted} B.C.G , is the triangle appoincted vnto , {COM:sic} which I muste make an equall likeiamme . (RECORD-E1-P1,1,D4R.343) And D , is the angle that the likeiamme must haue . (RECORD-E1-P1,1,D4R.344) Therfore first entendyng to erecte the likeia~me on the one side , that the ground line of the triangle whiche is B.G. I do draw a gemow line by C , and make it parallele to the ground line B.G , (RECORD-E1-P1,1,D4R.345) and that new gemow line is A.H . (RECORD-E1-P1,1,D4R.346) Then do I raise a line from B. vnto the gemowe line , which line is A.B and make an angle equally to D , (RECORD-E1-P1,1,D4R.347) that is the appointed angle {COM:no_matching_close_paren} accordyng as the .viij. co~clusion teacheth , (RECORD-E1-P1,1,D4R.348) and that angle is B.A.E . (RECORD-E1-P1,1,D4R.349) Then to procede , I doo parte in y=e= middle the said grou~d line B.G , in the prick F , fro~ which prick I draw to the first gemowe line A.H. an other line that is parallel to A.B , (RECORD-E1-P1,1,D4V.350) and that line is E.F . (RECORD-E1-P1,1,D4V.351) Now saie I that the likeia~me B.A.E.F , is equall to the triangle B.C.G. And also that it hath one angle {COM:no_matching_close_paren} that is B.A.E. like to D. the angle that was limitted . (RECORD-E1-P1,1,D4V.352) And so haue I mine intent . (RECORD-E1-P1,1,D4V.353) The profe of the equalnes of those two figures doeth depend of the .xli proposition of Euclides first boke , (RECORD-E1-P1,1,D4V.354) and is the .xxxi. proposition of this second boke of Theoremis , whiche saieth , that whan a tryangle and a likeiamme be made between .ij. selfe same gemow lines , and haue their ground line of one length , then is the likeiamme double to the triangle , wherof it foloweth , that if .ij. suche figures so drawen differ in their groundline onely , so that the ground line of the likeiamme be but halfe the ground line of the triangle , then be those .ij. figures equall , as you shall more at large perceiue by the boke of Theoremis , in y=e= .xxxi. theoreme . (RECORD-E1-P1,1,D4V.355) THE .XVI. CONCLVSION . (RECORD-E1-P1,1,D4V.357) TO MAKE A LIKEIAMME =L TO A TRIANGLE APPOINCTED , ACCORDYNG TO AN ANGLE LIMITTED , AND ON A LINE ALSO ASSIGNED . (RECORD-E1-P1,1,D4V.360) In the last conclusion the sides of your likeiamme wer left to your libertie , though you had an angle appoincted . (RECORD-E1-P1,1,D4V.362) Nowe in this conclusion you are somwhat more restrained of libertie sith the line is limitted , which must be the side of the likeia~me . (RECORD-E1-P1,1,D4V.363) Therfore thus shall you procede . (RECORD-E1-P1,1,D4V.364) Firste accordyng to the laste conclusion , make a likeiamme in the angle appoincted , equall to the triangle that is assigned . (RECORD-E1-P1,1,D4V.365) Then with your compasse take the length of your line appointed , (RECORD-E1-P1,1,D4V.366) and set out two lines of the same length in the second gemowe lines , beginnyng at the one side of the likeiamme , (RECORD-E1-P1,1,D4V.367) and by those two prickes shall you draw an other gemowe line , which shall be parallele to two sides of the likeiamme . (RECORD-E1-P1,1,D4V.368) Afterward shall you draw .ij. lines more for the accomplishement of your worke , whiche better shall be perceaued by a shorte exaumple , then by a greate numbre of wordes only without example , (RECORD-E1-P1,1,E1R.369) therefore I wyl by example sette forth the whole worke . (RECORD-E1-P1,1,E1R.370) Example . (RECORD-E1-P1,1,E1R.372) {COM:figure_omitted} Fyrst , according to the last conclusion , I make the likeiamme E.F.C.G , equal to the triangle D , in the appoynted angle whiche is E . (RECORD-E1-P1,1,E1R.375) Then take I the lengthe of the assigned line which is A.B , (RECORD-E1-P1,1,E1R.376) and with my compas I sette forthe the same le~gth in the ij. gemow lines N.F. and H.G , setting one foot in E , and the other in N , and againe settyng one foote in C. , and the other in H . (RECORD-E1-P1,1,E1R.377) Afterward I draw a line from N. to H , whiche is a gemow lyne , to ij. sydes of the likeiamme . (RECORD-E1-P1,1,E1R.378) thenne drawe I a line also from N. vnto C , (RECORD-E1-P1,1,E1R.379) and extend it vntyll it crosse the lines , E.L. and F.G , which both must be drawen forth longer then the sides of the likeiame . (RECORD-E1-P1,1,E1R.380) and where that lyne doeth crosse F.G , there I sette M . (RECORD-E1-P1,1,E1R.381) Nowe to make an ende , I make an other gemowe line , which is parallel to N.F and H.G , (RECORD-E1-P1,1,E1R.382) and that gemowe line doth passe by the pricke M , (RECORD-E1-P1,1,E1R.383) and then haue I done . (RECORD-E1-P1,1,E1R.384) Now say I that H.C.K.L , is a likeiamme equall to the triangle appointed , which was D , and is made of a line assigned that is A.B , (RECORD-E1-P1,1,E1R.385) for H.C , is equall vnto A.B , (RECORD-E1-P1,1,E1R.386) and so is K.L , (RECORD-E1-P1,1,E1R.387) The profe of y=e= equalnes of this likeiam vnto the tria~gle , depe~deth of the thirty and two Theoreme : as in the boke of Theoremes doth appear , where it is declared , that in al likeiammes , whe~ there are more then one made about one bias line , the filsquares of euery of them muste needes be equall . (RECORD-E1-P1,1,E1R.388) THE XVII. CONCLVSION . (RECORD-E1-P1,1,E1V.391) TO MAKE A LIKEIAMME = TO ANY RIGHT LINED FIGURE , (RECORD-E1-P1,1,E1V.394) AND THAT ON AN ANGLE APPOINTED . (RECORD-E1-P1,1,E1V.395) The readiest way to worke this conclusion , is to tourn that rightlined figure into triangles , and then for euery triangle to gether an equal likeiamme , according vnto the eleuen co~clusion , and then to ioine al those likeiammes into one , if their sides happen to be equal , which thing is euer certain , when al the triangles happe~ iustly betwene one pair of gemow lines . (RECORD-E1-P1,1,E1V.397) but and if they will not frame so , then after that you haue for the first triangle made his likeiamme , you shall take the le~gth of one of his sides , and set that as a line assigned , on whiche you shal make al the other likeiams , according to the twelft co~clusion , (RECORD-E1-P1,1,E1V.398) and so shall you haue al your likeiames with ij. sides equal , and ij. like angles , so y=t= you mai easily ioyne the~ into one figure . (RECORD-E1-P1,1,E1V.399) Example . (RECORD-E1-P1,1,E1V.401) {COM:figures_omitted} If the right lined figure be like vnto A , the~ may it be turned into triangles that will sta~d betwene ij. parallels anye ways , as you mai se by C and D , (RECORD-E1-P1,1,E1V.404) for ij. sides of both the tria~gles are parallels . (RECORD-E1-P1,1,E1V.405) Also if the right lined figure be like vnto E , the~ wil it be turned into tria~gles , liyng betwene two parallels also , as y=e= other did before , as in the exa~ple of F.G . (RECORD-E1-P1,1,E1V.406) But and if y=e= right lined figure be like vnto H , and so turned into tria~gles as you se in K.L.M , wher it is parted into iij tria~gles , the~ wil not all those triangles lye between one pair of parallels or gemow lines , (RECORD-E1-P1,1,E2R.407) but must haue many , (RECORD-E1-P1,1,E2R.408) for euery triangle must haue one paire of parallels seuerall , (RECORD-E1-P1,1,E2R.409) yet it maye hapen that when there bee three or fower triangles , ij. of theym maye happen to agre to one pair of parallels , whiche thinge I remit to euery honest witte to serche , (RECORD-E1-P1,1,E2R.410) for the manner of their draught wil declare , how many paires of parallels they shall neede , of which varietee bicause the examples are infinite , I haue set forth these few , that by them you may coniecture duly of all other like . (RECORD-E1-P1,1,E2R.411) {COM:figures_omitted} Further explicacion you shal not greatly neede , if you remembre what hath ben taught before , and then dilige~tly behold how these sundry figures be turned into tria~gles . (RECORD-E1-P1,1,E2R.413) In the fyrst you se I haue made v. triangles , and four paralleles . in the seconde vij. triangles and foure paralleles , in the thirde thre tria~gles , and fiue parallels , (RECORD-E1-P1,1,E2R.414) in the iiij. you se fiue tria~gles & four parallels . in the fifth , iiij. tria~gles and .iiij. parallels , (RECORD-E1-P1,1,E2R.415) & in y=e= sixt there are fiue tria~gles & iiij. paralels . (RECORD-E1-P1,1,E2R.416) Howbeit a ma~ maye at liberty alter them into diuers formes of tria~gles , (RECORD-E1-P1,1,E2R.417) & therefore I leue it to the discretion of the woorkmaister , to do in al suche cases as he shall thinke best , (RECORD-E1-P1,1,E2V.418) for by these examples if they bee well marked may al other like conclusions be wrought . (RECORD-E1-P1,1,E2V.419) THE XVIII. CONCLVSION . (RECORD-E1-P1,1,E2V.421) TO PARTE A LINE ASSIGNED AFTER SUCHE A SORTE , THAT THE SQUARE THAT IS MADE OF THE WHOLE LINE AND ONE OF HIS PARTS , SHAL BE = TO THE SQUAR {COM:sic} THAT COMETH OF THE OTHER PARTE ALONE . (RECORD-E1-P1,1,E2V.424) First deuide your lyne into ij. equal parts , (RECORD-E1-P1,1,E2V.426) and of the length of one part make a perpendicular to light at one end of your line assigned . (RECORD-E1-P1,1,E2V.427) then adde a bias line , (RECORD-E1-P1,1,E2V.428) and make therof a triangle , (RECORD-E1-P1,1,E2V.429) this done if you take from this bias line the halfe lengthe of your line appointed , which is the iuste length of your perpendicular , that part of the bias line whiche dothe remayne , is the greater portion of the deuision that you seke for , (RECORD-E1-P1,1,E2V.430) therefore if you cut your line according to the lengthe of it , then will the square of that greater $portion {TEXT:portior} be equall to the square that is made of the whole line and his lesser portion . (RECORD-E1-P1,1,E2V.431) And contrarywise , the square of the whole line and his lesser parte , wyll be equall to the square of the greater parte . (RECORD-E1-P1,1,E2V.432) Example . (RECORD-E1-P1,1,E2V.434) {COM:figure_omitted} A.B , is the lyne assigned . (RECORD-E1-P1,1,E2V.437) E. is the middle pricke of A.B , (RECORD-E1-P1,1,E2V.438) B.C. is the plumb line or perpendicular , made of the halfe of A.B , equall to A.E , other B.E , (RECORD-E1-P1,1,E2V.439) the byas line is C.A , from whiche I cut a peece , (RECORD-E1-P1,1,E2V.440) that is C.D , equall to C.B , (RECORD-E1-P1,1,E2V.441) and accordyng to the lengthe $of {TEXT:so} the peece that remaineth whiche is D.A , I doo deuide the line A.B , at whiche diuision I set E . (RECORD-E1-P1,1,E2V.442) Now say I , that this line A.B w=ch= was assigned vnto me is so diuided in this point F , y=t= y=e= square of y=e= hole line A.B , & of the one portio~ y=t= is F.B , the lesser part is equall to the square of the other parte , whiche is F.A , and is the greater part of the first line . (RECORD-E1-P1,1,E3R.443) The profe of this equalitie shall you learne by the .xl. Theoreme . (RECORD-E1-P1,1,E3R.444) THE .XIX. CONCLVSION . (RECORD-E1-P1,1,E3R.446) TO MAKE A SQAURE QUADRATE =L TO ANY RIGHT LINED FIGURE APPOINCTED . (RECORD-E1-P1,1,E3R.449) First make a likeiamme equall to that right lined figure , with a right angle , accordyng to the .xi. conclusion , (RECORD-E1-P1,1,E3R.451) then consider the liekiamme , whether it haue all his sides equall , or not : (RECORD-E1-P1,1,E3R.452) for yf they be all equall , then haue you doone your conclusion . (RECORD-E1-P1,1,E3R.453) but and if the sides be not all equall , then shall you make one right line iuste as long as two of those vnequall sides , (RECORD-E1-P1,1,E3R.454) that line shall you deuide in the middle , (RECORD-E1-P1,1,E3R.455) and on that pricke drawe half a circle , (RECORD-E1-P1,1,E3R.456) then cutte from that diameter of the halfe circle a certayne portion equall to the one side of the likeiamme , (RECORD-E1-P1,1,E3R.457) and from that pointe of diuision shall you erecte a perpendicular , which shall touche the edge of the circle . (RECORD-E1-P1,1,E3R.458) and that perpendicular shall be the iuste side of the square quadrate , equall both to the lykeiamme , and also to the right lined figure appointed , as the conclusion willed . (RECORD-E1-P1,1,E3R.459) Example . (RECORD-E1-P1,1,E3R.461) {COM:figures_omitted} K , is the right lined figure appointed , (RECORD-E1-P1,1,E3R.464) and B.C.D.E , is the likeia~me , with right angles equall vnto K , (RECORD-E1-P1,1,E3R.465) but because that this likeiamme is not a square quadrate , I must turne it into such one after this sort , (RECORD-E1-P1,1,E3R.466) I shall make one right line , as long as .ij. vnequall sides of the likeia~me , (RECORD-E1-P1,1,E3R.467) that line here is F.G , which is equall to B.C , and C.E . (RECORD-E1-P1,1,E3R.468) Then part I that line in the middle in the pricke M , (RECORD-E1-P1,1,E3V.469) and on that pricke I make halfe a circle , accordyng to the length of the diameter F.G . (RECORD-E1-P1,1,E3V.470) Afterward I cut awaie a peece from F.G , equally to C.E , markyng that point with H . (RECORD-E1-P1,1,E3V.471) And on that pricke I erecte a perpendicular H.K , whiche is the iust side to the square quadrate that I seke for , (RECORD-E1-P1,1,E3V.472) therfore accordyng to the doctrine of the .x. conclusion , of that lyne I doe make a square quadrate , (RECORD-E1-P1,1,E3V.473) and so haue I attained the practise of this conclusion . (RECORD-E1-P1,1,E3V.474) THE .XX. CONCLVSION . (RECORD-E1-P1,1,E3V.476) WHEN ANY .IJ. SQUARE QUADRATES ARE SET FORTH , HOW YOU MAIE MAKE ONE =L TO THEM BOTHE . (RECORD-E1-P1,1,E3V.479) First draw a right line equall to the side of one of the quadrates : (RECORD-E1-P1,1,E3V.481) and on the ende of it make a perpendicular , equall in length to the side of the other quadrate , (RECORD-E1-P1,1,E3V.482) then draw a byas line betwene those .ij. other lines , makyng thereof a right angeled triangle . (RECORD-E1-P1,1,E3V.483) And that byas lyne wyll make a square quadrate , equall to the other .ij. quadrates appointed . (RECORD-E1-P1,1,E3V.484) Example . (RECORD-E1-P1,1,E3V.486) {COM:figures_omitted} A.B. and C.D , are the two square quadrates appointed , vnto which I must make one equal square quadrate . (RECORD-E1-P1,1,E3V.489) First therfore I dooe make a righte line E.F , equall to one of the sides of the square quadrate A.B . (RECORD-E1-P1,1,E3V.490) And on the one end of it I make a plumbe line E.G , equall to the side of the other quadrate D.C . (RECORD-E1-P1,1,E3V.491) Then drawe I a byas line G.F , whiche beyng made the side of a quadrate accordyng to the tenth conclusion will accomplisshe the worke of this practise : (RECORD-E1-P1,1,E4R.492) for the quadrate H. is as muche iust as the other two . I meane A.B. and D.C . (RECORD-E1-P1,1,E4R.493) THE XXI. CONCLVSION . (RECORD-E1-P1,1,E4R.495) WHEN ANY TWO QUADRATES BE SET FORTH , HOWE TO MAKE A SQUIRE ABOUT THE ONE QUADRATE , WHICHE SHALL BE =L TO THE OTHER QUADRATE . (RECORD-E1-P1,1,E4R.498) Determine with your selfe about which quadrate you wil make the squire , (RECORD-E1-P1,1,E4R.500) and drawe one side of that quadrate forth in lengte {COM:sic} , accordyng to the measure of the side of the other quadrate , which line you maie call the grounde line , (RECORD-E1-P1,1,E4R.501) and then haue you a right angle made on this line by an other side of the same quadrate : (RECORD-E1-P1,1,E4R.502) Therfore turne that into a right cornered triangle , accordyng to the worke in the laste conclusion , by makyng of a byas line , (RECORD-E1-P1,1,E4R.503) and that byas lyne will performe the worke of your desire . (RECORD-E1-P1,1,E4R.504) For if you take the length of that byas line with your compasse , and then set one foote of the compas in the furthest angle of the first quadrate whiche is the one ende of the groundline and extend the other foote on the same line , accordyng to the measure of the byas line , and of that line make a quadrate , enclosyng y=e= first quadrate , then will there appere the forme of a squire about the first quadrate , which square is equall to the second quadrate . (RECORD-E1-P1,1,E4R.505) Example . (RECORD-E1-P1,1,E4R.507) {COM:figures_omitted} The first square quadrate is A.B.C.D , (RECORD-E1-P1,1,E4R.510) and the seconde is E . (RECORD-E1-P1,1,E4R.511) Now would I make a squire about the quadrate A.B.C.D , whiche shall bee equall vnto the quadrate E . (RECORD-E1-P1,1,E4R.512) Therfore first I draw the line A.D , more in length , accordyng to the measure of the side of E , as you see , from D. vnto F , (RECORD-E1-P1,1,E4V.514) and so the hole line of bothe these seuerall sides is A.F , (RECORD-E1-P1,1,E4V.515) the~ make I a byas line from C , to F , whiche byas line is the measure of this woorke , wherefore I open my compas accordyng to the length of that byas line C.F , (RECORD-E1-P1,1,E4V.516) and set the one compas foote in A , (RECORD-E1-P1,1,E4V.517) and extend thother foote of the compas toward F , makyng this pricke G , from whiche I erect a plumbe line G.H , (RECORD-E1-P1,1,E4V.518) and so make out the square quadrate A.G.H.K , whose sides are equall eache of them to A.G . (RECORD-E1-P1,1,E4V.519) And this square doth contain the first quadrate A.B.C.D , and also a squire G.H.K , whiche is equall to the second quadrate E , (RECORD-E1-P1,1,E4V.520) for as the last conclusion declareth , the quadrate A.G.H.K , is equall to bothe the other quadrates proposed , (RECORD-E1-P1,1,E4V.521) that is A.B.C.D , and E . (RECORD-E1-P1,1,E4V.522) Then muste the squire G.H.K. needes be equall to E , consideryng that all the rest of that great quadrate is nothyng els but the quadrate self , A.B.C.D , (RECORD-E1-P1,1,E4V.523) and so haue I thintent of this conclusion . (RECORD-E1-P1,1,E4V.524) THE .XXI. CONCLVSION . (RECORD-E1-P1,1,E4V.526) TO FIND OUT THE CE~TRE OF ANY CIRCLE ASSIGNED . (RECORD-E1-P1,1,E4V.529) Draw a corde or stryng line crosse the circle , (RECORD-E1-P1,1,E4V.531) then deuide into .ij. equall partes , both the corde , and also the bowe line , or arche line , that serueth to the corde , (RECORD-E1-P1,1,E4V.532) and from the prickes of those diuisions , if you draw an other line crosse the circle , it must nedes passe by the centre . (RECORD-E1-P1,1,E4V.533) Therfore deiude that line in the middle , (RECORD-E1-P1,1,E4V.534) and that middle pricke is the centre of the circle proposed . (RECORD-E1-P1,1,E4V.535) Example . (RECORD-E1-P1,1,E4V.537) {COM:figure_omitted} Let the circle be A.B.C.D , whose centre I shall seke . (RECORD-E1-P1,1,E4V.540) First therfore I draw a corde crosse the circle , (RECORD-E1-P1,1,E4V.541) that is A.C . (RECORD-E1-P1,1,E4V.542) Then do I deuide that corde in the middle , in E , (RECORD-E1-P1,1,E4V.543) and likewaies also do I deuide his arche line A.B.C , in the middle , in the pointe B . (RECORD-E1-P1,1,E4V.544) Afterward I drawe a line from B. to E , and so crosse the circle , which line is B.D , in which line is the centre that I seeke for . (RECORD-E1-P1,1,F1R.545) Therefore if I parte that line B.D , in the middle in to two equall portions , that middle pricke whiche here is F is the verye centre of the sayde circle that I seke . (RECORD-E1-P1,1,F1R.546) This conclusion may other waies be wrought , as the most part of conclusions haue sondry formes of practise , (RECORD-E1-P1,1,F1R.547) and that is , by makinge thre prickes in the circu~ference of the circle , at liberty where you wyll , and then finding the centre to these thre prickes , which worke bicause it serueth for sondry vses , I thinke meet to make it a seuerall conclusion by it selfe . (RECORD-E1-P1,1,F1R.548) THE XXIII. CONCLVSION . (RECORD-E1-P1,1,F1R.550) TO FIND THE COMMEN CENTRE BELONGYNG TO ANYE THREE PRICKES APPOINTED , IF THEY BE NOT IN AN EXACTE RIGHT LINE . (RECORD-E1-P1,1,F1R.553) It is to be noted , that though euery small arche of a greate circle do seeme to be a right lyne , yet in very dede it is not so , (RECORD-E1-P1,1,F1R.555) for euery part of the circumference of al circles is compassed , though in litle arches of great circles the eye $can $not {TEXT:cannot} discerne the crokendess , (RECORD-E1-P1,1,F1R.556) yet reason doeth alwaies declare it , (RECORD-E1-P1,1,F1R.557) therefore iij. prickes in an exact right line can not bee brought into the circumference of a circle . (RECORD-E1-P1,1,F1R.558) But and if they be not in a right line how so euer they stande , thus shall you find their com~on centre . (RECORD-E1-P1,1,F1R.559) Ope~ your compas so wide , that it be somewhat more then the halfe distance of two of those prickes . (RECORD-E1-P1,1,F1V.560) Then sette the one foote of the compas in the one pricke , (RECORD-E1-P1,1,F1V.561) and with the other foot draw an arche lyne toward the other pricke , (RECORD-E1-P1,1,F1V.562) then againe putte the foot of your compas in the second pricke , (RECORD-E1-P1,1,F1V.563) and with the other foot make an arche line , that may crosse the firste arch line in ij. places . (RECORD-E1-P1,1,F1V.564) Now as you haue done with those two prickes , so do with the middle pricke , and the thirde that remayneth . (RECORD-E1-P1,1,F1V.565) Then draw ij. lines by the poyntes where those arche lines do crosse , (RECORD-E1-P1,1,F1V.566) and where those two lines do meete , there is the centre that you seeke for . (RECORD-E1-P1,1,F1V.567) Example . (RECORD-E1-P1,1,F1V.569) {COM:figure_omitted} The iij. prickes I haue set to be A. B , and C , whiche I wold bring into the edg of one comon circle , by finding a centre co~men to them all , (RECORD-E1-P1,1,F1V.572) fyrst therefore I open my co~pas , so that they occupye more then y=e= halfe distance betwene ij. pricks as are A.B. (RECORD-E1-P1,1,F1V.573) and so settinge one foote in A. and extendinge the other toward B , I make the arche line D.E . (RECORD-E1-P1,1,F1V.574) Like wise setti~g one foot in B , and turninge the other toward A , I draw an other arche line that crosseth the first in D. and E . (RECORD-E1-P1,1,F1V.575) Then from D. to E , I draw a right lyne D.H . (RECORD-E1-P1,1,F1V.576) After this I open my co~passe to a new distance , (RECORD-E1-P1,1,F1V.577) and make ij. arche lines betwene B. and C , which crosse one the other in F. and G , by whiche two pointes I draw an other line , that is F.H . (RECORD-E1-P1,1,F1V.578) And bycause that the lyne D.H. and the lyne F.H. doo meete in H , I saye that H. is the centre that serueth those iij. prickes . (RECORD-E1-P1,1,F1V.579) Now therfore if you set one foot of your compas in H , and extend the other to any of the iij. prickes , you may draw a circle w=ch= shal enclose those iij. pricks in the edg of his circu~fere~ce , (RECORD-E1-P1,1,F1V.580) & thus haue you attained y=e= use of this co~clusio~ (RECORD-E1-P1,1,F1V.581) {COM:insert_helsinki_sample_2}