An electrostatic emission electron microscope, using a standard cathode ray tube, was demonstrated in 1934 at the University of Toronto by Walter Kohl, a visiting lecturer from Germany. This was likely the first example of electron microscopy of any kind in North America.

The first transmission EM constructed outside Germany was completed in 1935 or 1936 by Paul Anderson and Kenneth Fitzsimmons of Washington State University, Pullman, WA (Fig. 1A). In the same year, Gordon H. Scott at the Medical School of Washington University in St. Louis started an EM program, with an emission EM in 1935, and a transmission EM in 1939, constructed by Sterling Newberry (Fig. 1B). Neither of these programs continued, however, and resolution did not exceed that of the light microscope.

Also in 1935, E.F. Burton established an EM program at the University of Toronto, starting with a first instrument constructed by Cecil Hall, followed by the construction by James Hillier and Albert Prebus in 1938 of the first high-resolution EM in North America (Fig. 1C).

Hillier and Prebus were succeeded by William Ladd and John H.L. Watson, who refined the EM to yield a resolution of better than 10 nm in 1939, matching the performance of the German EMs at the time.

Hillier was subsequently hired by Alexander Zworykin (a pioneer in the development of television), and went on design highly successful electron microscopes for RCA, eventually becoming overall head of research at RCA.