<p style='text-align: justify;'>The <i>Margarita philosophica</i> was a compendium, or 'Epitome' of university learning in the sixteenth century. It was written by the prior of the house of Carthusians at Freiburg, Gregor Reisch (d. 1525), and was first published in 1503 in Freiburg by Johannes Schott, a printer from Strasbourg. The work was illustrated amply with somewhat crude woodcuts, and was divided into twelve books, with one book each dealing with the trivium (grammar, dialectic and rhetoric) and quadrivium (arithmetic, music, geometry, astronomy), four books devoted to natural philosophy, and one book on moral philosophy. It was a popular work, reprinted numerous times during the sixteenth century, including the unauthorized, augmented editions by another printer at Strasbourg, Johann Grueninger. Oronce Fine edited and added to the Latin text of the 1535 edition. In the 1512 edition, Grueninger attached an appendix consisting of material not discussed extensively in the original Schott edition. This appendix included Greek and Hebrew alphabets, musical notation, perspective and architecture, and explanation of such instruments as the quadrant, astrolabe, and torquetum. In book 7, the <i>Margarita</i> includes a summary of Peuerbach's <i>Theoricae novae planetarum</i> and reproduces some of its original diagrams. This one is an improved copy of the diagram that represents the orbs of the superior planets in Peuerbach's original (c. 1474) edition. Saturn has three orbs, similar to the orbs of the Sun except that its middle eccentric orb contains an epicycle. The outermost orb, printed black, is said to be 'deformed' (its two surfaces are not concentric): its exterior convex surface is concentric with the World (<i>c. mundi</i>), while the centre of its concave surface is the centre of the eccentric deferent (<i>c. deferentis</i>). The innermost orb, printed black, is also 'deformed': the centre of its interior concave surface is the centre of the World, while the centre of its exterior convex surface is the centre of the eccentric deferent. These two deformed orbs are the deferent orbs of the apogee (<i>orbes augem deferentes</i>). They move 'by virtue of the motion of the eighth sphere on the axis and poles of the ecliptic' (<i>virtute motus octavae sphaerae super axe et polis eclipticae moventur</i>). The apogee (<i>aux</i>) and perigee (<i>oppositum augis</i>) are marked on the diagram. The vertical line is the axis of the deferent orbs of the apogee, marked 'line of the apogee' (<i>linea augis</i>). The white orb sandwiched between these orbs is eccentric to the centre of the World on both its inner and outer surfaces. The centre of the epicycle (<i>epicyclus</i>) is attached to the circle in the middle of this orb (marked '<i>deferens</i>'). Both orb and circle are called the eccentric deferent of the planet. The eccentric deferent 'moves eastward on its axis, which intersects the axis of the ecliptic, and its poles are separated from the poles of the zodiac by unequal distances' (<i>super axe suo axem zodiaci secante secundum successionem Signorum movetur, et poli eius distant a polis zodiaci distantia non aequali</i>). As is explained later (sig. R1r), the intersection between the axis of the eccentric and the axis of the deferent is not at the centre of the World, and the north poles of the deferent and ecliptic are closer together than the corresponding south poles. Around the three orbs of Saturn, a starry zodiac is represented (<i>zodiacus in firmamento</i>). A circle labelled 'equant' (<i>equans</i>) intersects the eccentric circle on which the centre of the epicycle is attached (<i>deferens</i>). This equant circle was not drawn in the original c. 1474 diagram. Its centre (<i>c. equantis</i>) is above the centre of the deferent, as distant from it as the deferent is from the centre of the World, so that the centre of the deferent is in the middle of the centre of the equant and the centre of the World. In the fifteenth-century glossary of astronomical terms edited by Olaf Pedersen, the 'eccentric equant' (<i>eccentricus equans</i>) is defined as 'a circle in relation to whose centre the centre of the epicycle moves regularly and describes equal angles in equal times; its centre is as distant from the centre of the deferent, as the centre of the deferent from the centre of the Earth' (<i>quidam circulus supra cuius centrum equaliter movetur centrum epicycli, et in temporibus equalibus equales angulos describit, cuius centrum tam distat a centro deferentis quam centrum deferentis a centro Terrae</i>). '<i>Equans</i>' is a term used only in the theory of Mercury, Venus, and the three superior planets, not in the theory of the Sun nor even the theory of the Moon, in which the term 'opposite point' (<i>punctum oppositum</i>) is used. Peuerbach specifies that the movement of the centre of the epicycle (which is uniform in relation to the centre of the equant) is slower (in relation to the centre of the deferent) near the apogee of the deferent and faster near the perigee, which is 'the opposite of what happens in the case of the Moon'. Translated quotations of Peuerbach's <i>Theoricae</i> are from Aiton (1987). Other quotations (translated by Isabelle Pantin) are from Pedersen (1973).</p>
