KAESTNER, Abraham Gotthelf (1719-1800). Dissertationes Mathematicae et Physicae, Altenburg: ex officina Richteria, 1771, 4°, 6 folding engraved plates (library markings, including title perforation and stamp on verso of each plate), contemporary calf-backed boards (spine worn and with library label) Provenance: JCL; and a copy of Gaspar Ens' Thaumaturgus mathematicus (Cologne, 1636), lacking title page. (2)