THE recent issue of Isis (pp. 81-97) contains an important paper by Mr. W. Cameron Walker on “The Beginnings of the Scientific Career of Joseph Priestley”, disposing of the incorrect views expressed by Priestley's biographers, such as, that his “History of Electricity” was suggested by Franklin and that it led to his election as F.R.S., that this distinction was the result of his electrical experiments, and so on. The Canton Papers and certain letters-some facsimiles are given-in the Royal Society's library show that the writing of the “History” was Priestley's own idea, that he was elected F.R.S. prior, not only to its publication, but also to his experiments, and that his friends secured his election with the view of increasing the sale of his book. Priestley's own account, written long after these events, ascribed his election to his original experiments. But the author is probably correct in hinting at a lapse of memory, since there is other evidence of this failing. The most interesting document here is Seddon's letter of December 18, 1765, introducing Priestley to Price and suggesting in a postscript his introduction to Franklin. As a result Priestley met Franklin and Canton, was elected F.R.S., was led to experiment in electricity, thence to the study of the conductivity of ‘mephitic air’, and thence to his classic chemical researches on ‘airs’ and to the discovery of oxygen to the birth of modern chemistry. Few ‘postscripts’ have had such historic consequences.