William J. Canby, grandson of the seamstress Betsy Ross, read a paper in March, 1870 in the Pennsylvania Historical Society relating for the first time in public his family's tradition that Betsy Ross (Elizabeth Claypoole) made the first U.S. American flag. His theory was criticized for the lack of corroborative evidence. Upon Canby's death, his brother George continued research on the story, and his findings were published by Lloyd Balderston in The evolution of the American flag / from materials collected by the late George Canby; by Lloyd Balderston (Philadelphia : Ferris & Leach, 1909).
From the description of Papers of William J. Canby, 1758-1975 (bulk 1905-1975). (Huntington Library, Art Collections & Botanical Gardens). WorldCat record id: 122396733
