""Joseph Warburton (1786-1846) of Pateley Bridge and his assistant Dr John Snow.""
PDF is a scanned copy of an off-print given to PVJ by the author.
Please note: Galbraith decided to identify Snow as a Dr. in the title of this article, even though he had no medical credentials other than completion of his apprenticeship at the time he assisted Warburton, a licensed apothecary.
Editorial changes in footnotes on pp. 234-35 are by Galbraith.