KOHLHAUSEN, JOHANN CHRISTOPH. Neu-erfundene Mathematische und Oprische Curiositäten. Leipzig: Johann Nisius, 1677. 24 engraved plates (3 folding) -- HARTNACCIUS, DANIELE. Perspectiva Mechanica und Eigentliche Beschreibung derer vornehmsten Instrumenten... Lüneburg: Ben Johann Kelpen/Druckts Martin Vogel, 1683. 4 engraved plates and one woodcut illustration on final blank recto. Together 2 works in one, small 4to, old vellum; later endpapers (?), some browning of text in second work; owner's stamp on title and front cover.