FRANKLIN, Benjamin. Experiments and Observations on Electricity, Made at Philadelphia in America...To Which Are Added, Letters and Papers on Philosophical Subjects. The Whole Corrected, Methodized, Improved, and Now First Collected into One Volume, and Illustrated with Copper Plates. London: Printed for David Henry, and sold by Francis Newbery, 1769. ,iv,,496[i.e. 510, accounting for mispagination, plus four extra pages where the page numbers have been duplicated, i.e. page numbers 112-113 and 416-417 appear twice],pp. Including leaf of errata and advertisement "concerning this fourth edition." Illustrations plus seven engraved plates (two folding). 4to. Orig. 18th-century speckled calf, double-ruled in gilt, expertly rebacked in matching speckled calf, gilt-decorated raised spine bands, compartments gilt, original red leather spine label laid down, chamfered in blind. With mid-19th-century ownership signature and later bookplate. Faint scattered foxing, a few leaves lightly toned at margins, else very good or better. HOWES F-320, "b." Printing and the Mind of Man 199. Sabin 25506. Ford 307. Milestones of Science 69. "America's first great scientific contribution" - Howes. This is the fourth, first collected, and by far most desirable edition, containing for the first time complete notes on all the experiments, as well as correspondence between Peter Collinson, Franklin, and other collaborators. Franklin began experimenting with electricity as early as 1745, demonstrating the electrical property of lightning and inventing the lightning conductor. This volume includes summaries of his work with Leyden jars, charged clouds, and lightning rods, as well as his famous kite and key experiment. In addition to the electrical experiments it contains the important discovery of the course of storms over North America and other important meteorological observations. The work caused a sensation in the scientific world when first published in 1751, and ranked in the eyes of many of Franklin's contemporaries as far beyond any of his political achievements. Harvard and Yale awarded him honorary degrees in 1753; he received the highest award of the Royal Society, the Copley Medal, the same year; and he was elected to the Society in 1756, the first.