Carlyn Nichols's List: History of Microscope

• Electron Microscope Magnifies Atoms 

   

    By the twentieth century the essential design and shape of the compound  microscope had evolved into the same form we know today. Microscopes used  in schools and small laboratories can achieve magnification of up to 400  power. More advanced microscopes used in research laboratories can magnify  a specimen to almost 1000 power. These research microscopes often have  binocular eyepieces, which rely upon a series of prisms to split the image  so that it may be viewed with both eyes. Even trinocular microscopes have  been designed, which create a third image for a camera to view. 

   

    The practical limit for any compound microscope is 2,500 power. In the  twentieth century this limited magnification capability frustrated  scientists who were anxious to view the world on submicroscopic and  subatomic levels. In 1931 German scientist Ernst Ruska (1906-1988)  constructed the electron microscope, thus permitting such investigations. 

   

    Designed much like a compound microscope, the electron microscope uses a  beam of electrons focused through magnetic lenses. Since electrons possess  much smaller wavelengths than does visible light, the electron microscope  can provide much higher magnification than light-based instruments.  Through electron microscopes scientists first viewed strands of DNA. Since  Ruska's invention, instruments such as the scanning tunneling  microscope and the field ion microscope have been developed.   These devices are capable of observing the activities and structures of  individual atoms.

• In his classic work     Rats, Lice and History    (1935), the microbiologist Hans Zinsser vividly describes how the outcome  of wars has often been decided by which side was more successful in  withstanding the deaths from typhus among its fighting forces.
• The  European conquest of the Americas and colonization of the rest of the  world was materially assisted by the impact of measles, smallpox, and  tuberculosis on the people who had been there before them. Europeans had  some inherent resistance to those diseases after many centuries of  exposure had weeded out those most susceptible.
• sanitary revolution
• An understanding of what is causing it.    John Snow, the English physician who investigated the cholera epidemics  in London in the 1840s and 1850s, provided evidence that the disease was  spread by polluted drinking water. The cholera vibrio, the causative  organism, was not discovered until about thirty years later, but  recognition that polluted water was spreading cholera enabled some  preventive action—provision of clean water supplies—to  begin
• electron microscope
• high-quality microscopes and the techniques of bacterial culture

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