Signedstamped on envelope: EDMUND SALVAGE COMPANY / OAKLYN-AUDUBON, NEW JERSEY
Inscribedstamped on envelope: TWO LENSES COMBINE / TO MAKE AN ACHROMAT / DIAMETER 48 MILLIMETERS / FOCAL LENGTH 11 INCHES
stamped in envelope corner: REFLECTION / [illegible]
ProvenanceSalvaged from the Science Center Prep Room, courtesy of Prof. Owen Gingerich.