The form of an ellipse; and of the original reality of the true side of the Glass ustorii; Setting up a burning mirror to set a ship afire by the sun; Fig. 1; p. 764; Kircher; Athanasius; 1671; Athanasius Kircher: Athanasii Kircheri [...] Ars magna lucis et umbrae; in X. libros digesta: quibus admirandae lucis et umbrae in mundo; atque adeo universa natura; vires effectusque uti nova; ita varia novorum reconditiorumque speciminum exhibitione; ad varios mortalium usus; panduntur. Amstelodami [Amsterdam]: apud Ioannem Ianssonium ?Waesberge [etc.]; 1671