What Did Zacharias Janssen Invent?

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Zacharias Janssen invented the first compound microscope. Zacharias and his father, Hans, originally made eyeglasses, or spectacles, but Hans Janssen may have contributed to his son's invention. Although the first microscopes Janssen made were crude by modern-day standards, they did lead to the development of better scientific instruments.

The first compound microscopes developed by Zacharias Janssen in the 1590s were hulks compared to modern-day versions. The tripod itself measured more than two feet in height. The actual instrument was a tube equipped with two lenses, a convex lens at one end and a concave one at the other. One lens bent the light; the other magnified the image.

The first microscopes only magnified images between three and nine times the size of the actual object. More than half a century would pass before the compound microscope would be in widespread use in the scientific community.