FRANKLIN, BENJAMIN. Experiments and Observations on Electricity, made at Philadelphia in America. London: Printed and sold by E. Cave, 1751. Engraved folding plate -- Supplemental Experiments and Observations on Electircity [sic.], Part II. Made at Philadelphia in America. London: E. Cave, 1753 -- New Experiments and Observations on Electricity. Made at Philadelphia in America...Part III. London: D. Henry and R. Cave, 1754. Woodcut text illustration. 3 parts in one volume, 4to, contemporary calf, rebacked, upper joint cracked; title slightly age-darkened at edges, closed tear to folding plate (on unprinted portion and not affecting image). FIRST EDITIONS, Part 1 with final leaf of advertisements. Dibner 57; Grolier/Horblit 31a; Howes F320; Sabin 25505; PMM 199.