"A weak mind is like a microscope, which magnifies trifling things, but cannot receive great ones"
Lord Chesterfield, English aristocrat
The first microscopes were made around 1590 by the father and son team of Hans and Zacharias Jansen. These Dutch spectacle-makers fashioned a microscope with a magnification of just twenty times.
In 1673 Dutch Antony van Leeuwenhoek discovered bacteria (animacules), blood cells, protozoa, and spermatozoa with a microscope that magnified objects by 300 times. By 1886 Ernst Abbe had advanced the technique quite considerably, and his microscope reached the limits of resolution with visible light— about 2,000 angstroms, or 0.0002 millimeters. But to get better resolution you need something with a smaller wavelength. Ernst Ruska (1906-1988) and his professor, Max Knoll (1897-1969), realized that if electrons were accelerated in a vacuum, their wavelength could be one hundred thousandths that of visible light. These electron beams could then be focused with magnetic coils to produce images. He built the first electron microscope in 1931. Ironically, it had worse resolution than the Jansens' microscope. But by 1933 Ruska had made an electron microscope with a resolution that exceeded that of visible light microscopes, and by 1939 the first commercially available electron microscopes were built. Ruska was awarded half of the 1986 Noble Prize in Physics for his development of the electron microscope.
