(Berlin, Haude et Spener, 1759). 4to. No wrappers, as issued in ""Mémoires de L'Academie Royale des Sciences et belles-Lettres"", tome XIII, 1757. With titlepage to the year 1757 with engraved titlevignette and pp. 125-159 and 1 folded engraved plate. A Stamp to titlepage.
First appearance of this paper which expands his prize-winning memoir from the Petersbourg Academy. He is now convinced by Aepinus of the importence of Franklin's distinction between positive and negative electricity. He elaborates his theory of the identity of the electrical fluid with the ether.