FRESCHEUR, Franciscus David and LOHMEIER, Philip.

Second edition of this scarce doctoral thesis on aeronautics and flying machines, first published 1676, the same year as the original disputation.
The idea for the kind of flying machine discussed here had originated with the Jesuit priest Francesco Lana Terzi (1631-87), who in his Prodromo of 1670 had described a flying ship that worked by vacuum. Lana's plausible theory was that a body will rise into the air if it is lighter than the air of the volume that it displaces. This was enthusiastically taken up by Philip Lohmeier (1648-80), professor of physics at the University of Rinteln, who then examined his student Frescheur on the subject in his dissertation. Lohmeier was probably the substantive author of this work, and it was Lohmeier who was subsequently accused of plagiarising Lana's ideas.
The dissertation describes the possibilities of such an invention for exploration of the oceans and in the remotest regions, as well as ascending above the highest mountains, which prompts a discussion of the density of the atmosphere at high altitudes, using as an example attempts by the Spanish to traverse high mountains in Nicaragua and Peru on horseback. It relies upon advancements made in 'recent experiments', including Robert Boyle's experiments on air pressure using a vacuum pump, as described in his New Experiments (1660), mentioned here with reference to specific experiments, along with experiments on liquids in Hydrostatical Paradoxes (1666). The remainder of the disputation examines the physical properties of air and water in various circumstances and at various densities, altitudes and depths, etc., including with reference to oceans and rivers.
Lohmeier's and Frescheur's disputation remained of interest into the balloon age, with reprints in 1708 and 1784, the latter the year after the first balloon flight by the Montgolfier brothers.