. The electron microscope, its development, present performance and future possibilities. Electron microscopes. Theory of the Electron Microscope 145 By proving the advantage of oblique illumination, Abbe's theory proved to be of great heuristic value, as it led to the wide angle condenser which was one of the most important improvements in the history of the microscope. But in pointing toward wide angle illumination, the theor}^ pointed beyond itself. It was soon found experimentally that it is better to fill the cone of the objective aperture entirely or almost entirely * with light, than to
. The electron microscope, its development, present performance and future possibilities. Electron microscopes. Theory of the Electron Microscope 145 By proving the advantage of oblique illumination, Abbe's theory proved to be of great heuristic value, as it led to the wide angle condenser which was one of the most important improvements in the history of the microscope. But in pointing toward wide angle illumination, the theor}^ pointed beyond itself. It was soon found experimentally that it is better to fill the cone of the objective aperture entirely or almost entirely * with light, than to use hollow cones with nearly marginal rays, and here the simple assumptions of the original Abbe theory were obviously not fulfilled. It was suspected that Abbe had over- emphasized the importance of coherence, and this view received strong support, in 1896, when Lord Rayleigh showed that if the light source is sharply focused on the object, it will become almost exactly equivalent to a self-luminous object, as different. a) Centra? beam only. Intensity/.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Gabor, Dennis, 1900-. Brooklyn, Chemical Pub. Co.
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