Back to main Website 1579 Michael MAIER. De circulo physico, quadrato: hoc est, Auro, eiusque virtute medicinali, sub duro cortice instar nuclei latente; An et qualis inde petenda sit, Tractatus haud inutilis. 4° Oppenheimii: typis Hieronymus Galleri, sumptibus Lukas Jennis 1616 Ferguson British Library Wisconsin [Illustration:- Engraving on title-page. 74x74mm. A square within a circle, associating the four elements with the four qualities.]