DEMONVILLE, Antoine Louis Guénard. ~ Mémoire explicatif des phénomènes de l’aiguille aimantée, pour faire suite à la Question de Longitude sur mer au moyen d’une sphère-pendule par Demonville. Paris: [Bacquenois et Appert] chez l’auteur, 1833.
, 46-92,  (adverts), plus 2 lithograph charts, one very large (700 × 540 mm) on two sheets and folding. First few leaves somewhat browned. Uncut and partly unopened in original printed wrapper. A very good copy.
First separate edition, also issued simultaneously as a suite to the author’s Question de longitude sur mer (1833), but here issued alone with its own title-page and errata leaf forming a wrapper. The final 4 leaves are adverts for the author’s controversial mechanical planispheres, one of which is illustrated in the very large folding plate.
Demonville had been a printer (and the son of a printer to the Académie française) but diversified as a maker of globes scientific instruments after losing his licence to print in Paris. In the year of publication, he acquired notoriety as an astronomical crank who denied the astronomy of Copernicus, Galileo, Newton, Halley and Herschel. His planispehere demonstrates his alternative system: the earth, the sun and the moon are the only astronomical bodies; the earth does not rotate (it merely nods a little over the course of a year); the moon is 250 leagues from the earth and the sun, just 1500; the stars are affixed to the crystalline sphere; and the planets have no corporeal existence. Demonville hawked his system (with both books and his instruments) around Paris and London, even obtaining an audience with William III, who asked the Royal Society for their opinion. With his longitude pamphlets he sought to obtain prizes from the Societies of Paris and London but ideas were roundly dismissed, and Demonville pilloried in the press. Both issues rare.