Description: [caption id="" align="aligncenter" width="425" caption="National Portrait Gallery museum aide Betsy Heck demonstrating the use of Charles Willson Peale's physignotrace. Portrait of Peale at left, Date unknown, by Unidentified photographer, Photographic print, Smithsonian Institution Archives Record Unit: 371, Box: 1, Folder: October 1986, Negative Number: 66671."][/caption]