Zacharias Janssen

Zacharias Janssen (ca.1580-ca.1638) was a Dutch spectacle-maker of Middelburg, son of Hans Janssen. He is sometimes given the credit for inventing the first compound microscope, probably with the help of his father in the year 1590, although the origin of the microscope is a matter of debate.

Reproduction of first compound microscope made by Hans and Zachias Janssen, circa 1590.

Zacharias' brother would later testify under oath that Hans Lippershey, also from Middelburg, had stolen his father's idea for a microscope. However, this is supposed to have occurred at a time when Janssen would have been only 2 years old. Since Zacharias was very young at that time, it is possible that his father Hans made the first one, and young Zacharias took over the production.

The first crude compound microscope produced by the Janssens was simply a tube with lenses at each end. The magnification of these early microscopes ranged from 3X to 9X, depending on the size of the diaphragm openings.

References

• Zacharias Janssen, Michael W. Davidson, The Florida State University
• Helen Purtle, "History of the Microscope," Encyclopedia of Microscopy and Microtechnique, (New York: Van Nostrand Reinhold Co., 1973). Article also published in Helen Purtle (ed), The Billings Microscope Collection of the Medical Museum, Armed Forces Institute of Pathology (2nd edition), (Washington: Armed Forces Institute of Pathology, 1974).

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