The Contents.
Booke I. Of a Magnitude. Page 1
Booke II. Of a Line. p. 13
Book III. Of an Angle. p. 21
Book IV. Of a Figure. p. 32
Book V. Of Lines and Angles in a plaine Surface. p. 51
Book VI. Of a Triangle. p. 83
Book VII. The comparison of Triangles. p. 94
Book VIII. Of the diverse kinds of Triangles. p. 106
Book IX. Of the measuring of right lines by like right-angled Triangles. p. 113
Book X. Of a Triangulate and Parallelogramme. p. 136
Book XI. Of a Right-angle. p. 148
Book XII. Of a Quadrate. p. 152
Book XIII. Of an Oblong. p. 167
Book XIV. Of a right line proportionally cut: And of other Quadrangles, and Multangles. p. 174
Book XV. Of the Lines in a Circle. p. 201*
Book XVI. Of the Segments of a Circle. p. 201
Book XVII. Of the Adscription of a Circle and Triangle. p. 215
Book XVIII. Of the adscription of a Triangulate. p. 221
Book XIX. Of the measuring of ordinate Multangle, and of a Circle. p. 252*
Book XX. Of a Bossed surface. p. 257*
Book XXI. Of Lines and Surfaces in solids. p. 242
Book XXII. Of a Pyramis. p. 249
Book XXIII. Of a Prisma. p. 256
Book XXIV. Of a Cube. p. 264
Book XXV. Of mingled ordinate Polyedra's. p. 271
Book XXVI. Of a Spheare. p. 284
Book XXVII. Of the Cone and Cylinder. p. 290
VIA REGIA AD GEOMETRIAM.
THE FIRST BOOKE OF Peter Ramus's Geometry, Which is of a Magnitude.
1. Geometry is the Art of measuring well.
The end or scope of Geometry is to measure well: Therefore it is defined of the end, as generally all other Arts are. To measure well therefore is to consider the nature and affections of every thing that is to be measured: To compare such like things one with another: And to understand their reason and proportion and similitude. For all that is to measure well, whether it bee that by Congruency and application of some assigned measure: Or by Multiplication of the termes or bounds: Or by Division of the product made by multiplication: Or by any other way whatsoever the affection of the thing to be measured be considered.
But this end of Geometry will appeare much more beautifull and glorious in the use and geometricall workes and practise then by precepts, when thou shalt observe Astronomers, Geographers, Land-meaters, Sea-men, Enginers, Architects, Carpenters, Painters, and Carvers, in the description and measuring of the Starres, Countries, Lands, Engins, Seas, Buildings, Pictures, and Statues or Images to use the helpe of no other art but of Geometry. Wherefore here the name of this art commeth farre short of the thing meant by it. (For Geometria, made of Gè, which in the Greeke language signifieth the Earth; and Métron, a measure, importeth no more, but as one would say Land-measuring. And Geometra, is but Agrimensor, A land-meter: or as Tully calleth him Decempedator, a Pole-man: or as Plautus, Finitor, a Marke-man.) when as this Art teacheth not only how to measure the Land or the Earth, but the Water, and the Aire, yea and the whole World too, and in it all Bodies, Surfaces, Lines, and whatsoever else is to bee measured.
Now a Measure, as Aristotle doth determine it, in every thing to be measured, is some small thing conceived and set out by the measurer; and of the Geometers it is called Mensura famosa, a knowne measure. Which kinde of measures, were at first, as Vitruvius and Herodo teache us, taken from mans body: whereupon Protagoras sayd, That man was the measure of all things, which speech of his, Saint Iohn, Apoc. 21. 17. doth seeme to approve. True it is, that beside those, there are some other sorts of measures, especially greater ones, taken from other things, yet all of them generally made and defined by those. And because the stature and bignesse of men is greater in some places, then it is ordinarily in others, therefore the measures taken from them are greater in some countries, then they are in others. Behold here a catalogue, and description of such as are commonly either used amongst us, or some times mentioned in our stories and other bookes translated into our English tongue.
Granum hordei, a Barley corne, like as a wheat corne in weights, is no kinde of measure, but is quiddam minimum in mensura, some least thing in a measure, whereof it is, as it were, made, and whereby it is rectified.
Digitus, a Finger breadth, conteineth 2. barly cornes length, or foure layd side to side:
Pollex, a Thumbe breadth; called otherwise Vncia, an ynch, 3. barley cornes in length:
Palmus, or Palmus minor, an Handbreadth, 4. fingers, or 3. ynches.
Spithama, or Palmus major, a Span, 3. hands breadth, or 9. ynches.
Cubitus, a Cubit, halfe a yard, from the elbow to the top of the middle finger, 6. hands breadth, or two spannes.
Ulna, from the top of the shoulder or arme-hole, to the top of the middle finger. It is two folde; A yard and an Elne. A yard, containeth 2. cubites,