I purchased the book, Auguste Edouart's Silhouettes of Eminent Americans, 1839-1844 by Andrew Oliver (1977) for $12 through Amazon.com. I was looking for images of silhouettes of the Ball Hughes family.
According to the Appendix, Edouart cut four silhouettes of the Ball Hughes family in Boston on Nov. 2, 1842, including the two that I knew about and have on my Silhouettes webpage on RobertBallHughes.com. They are recorded as "Hughes, Ball, sculptor from London, doing a bust of Edouart" and "Hughes, Mrs. Ball." The book by Oliver is apparently an edited version of the 1926 book by Emily Jackson by the same name.
According to the Appendix to the book, Edouart also did a silhouette of Ball Hughes daughter Augusta and one of daughter Georgina at the same time as the ones above. Unfortunately, none of the four Ball Hughes family silhouettes appear in Oliver's book. I'd like to know if they are in Jackson's 1926 book or if anyone has images that they can share with me.
Once again my research answers one question and creates another. I learned from the book that the silhouettes were done in 1842 in Boston and this is very helpful. I also learned that there are two more silhouettes that I didn't know about and don't have images of (yet).