1To James Madison from Thomas Ewell, 23 May 1813 (Madison Papers)
...established that 85 yds. in the Brass Eprouvette—was equal to over 200 in the Iron...
2To James Madison from Thomas Ewell, 27 July 1813 (Abstract) (Madison Papers)
...by Catalano having been allowed to load the eprouvette, and asked that Ewell’s powder be tried...