‎"ÆPINUS (AEPINUS), FRANZ ULRICH THEODOSICUS. - THE ANALOGY BETWEEN ELECTRICITY AND MAGNETISM.‎
‎Mémoire concernant quelques nouvelles Experiences électriques remarquables.‎

‎Berlin, Haude et Spener, 1758. 4to. No wrappers, as issued in ""Mémoires de l'Academie Royale des Sciences et Belles-Lettres"", 1756, tome XII. Pp. 105-121. With titlepage to the volume, printed in red/blac and with engraved titlevignette. Also having the parttitlepage. Titlepage with 2 small wormtracts.‎

Reference : 46557

‎First appearance of a milestone paper in the history of electricity as Aepinus here found that a heated tourmaline attracted and repelled light bodies. He decided, that the effect was electrical and that its ends was carrying charges of opposite sign, much as soft iron is magnetized by a lodestone. This paper is a forerunner of his ""Tentamen Theoriae electricitatis et magnetismi"", - published 1759, and one of the most original and important books in the history of electricity. It is the first reasoned, fruitful exposition of electrical phenomena based on action-at-a-distance.""Aepinus’ first reseraches on the thermoelectric properties of this stone (Tourmalin) which was then of extreme rarity, were fundamental. He recognized the electrical nature of the attractive power of a warmed tourmaline and attempted not altogether successfully, to reduce its apparent capriciousness to rule. He was particularly struck by the formal similarity between the tourmaline and the magnet in regard to polarity which inspired him to reconsider the possibility, then occasionally discussed, that electricity and magnetism were basically analogous. This thought became the This thought became the theme for his masterwork, Tentamen theoriae electricitatis et magnetismi (1759).""(DSB).""Aepinus is known in the history of electricity for his attempt to develop the one fluid theory of Franklin. His theory was for a while generally adopted, but was gradually displaced by the two fluid theory, in consequence chiefly of the necessity of ascribing to uncharged matter repulsions of the same force as those which were ascribed to electrical charges. His theory exhibits interesting similarities to the present theory of the constitution of matter""(Magie ""A Source Book in Physics"", pp.406-8).Ronalds p. 4.‎