[2], v, [1], 514, [16] pp. Illustrated with 7 copper-engraved plates, 3 of which are folding; extra-illustrated with copper-engraved portrait of Franklin from a French publication, dated 1777, inserted before the title-page (this portrait backed). (4to) 22.5x16.5 cm. (9x6½"), period calf, rebacked with later gilt-ruled calf with edges restored, raised spine bands, morocco lettering piece, new endpapers. Fifth Edition in English.

Second complete edition of "the most important scientific book of eighteenth-century America" (PMM) - following the fourth edition of 1769 - together with printings of other texts. Earlier editions of Franklin's electricity were published in separate parts. "The most dramatic result of Franklin's researches was the proof that lightning is really an electrical phenomenon. Others had made such a suggestion before him--even Newton himself--but it was he who provided the experimental proof. In 1752 he flew a kite in a thunderstorm and attached a key to its string. From this he collected electric charges in a Leiden jar and showed that atmospheric and frictional or machine-made electricity are the same...His reputation as a scientist was immediately established by the publication of the results of his researches in a series of letters addressed to Peter Collinson, a London merchant and naturalist..." (PMM). The first edition was published between 1751 and 1754. PMM 199 (1st Ed); Sabin 25506; Waller 11340; Wellcome III, p.62. Old slip of paper (original endpaper?) inscribed "To the Free Library Richmond, September 1881" affixed to front pastedown, with that institution's discard rubberstamp on title-page verso; "Richmond" stamped in gilt on spine, with a paper spine label and trace from removal of another.