Two optically plane glass plates, each 2" square, 1/4" thick, for demonstrating interference fringes produced by thin films Two optically plane glass plates
Six circular glass plates bearing negatives made with a Stirn waist coat camera (three dated 1889), plus two unexposed plates; all in original box. Six circular glass plates bearing negatives made with a Stirn waist coat camera (three dated 1889) 1889