Who invented the microscope in 1666

Optical lenses

The first microscopes appeared - like the first telescopes - in the 17th century in Holland, where the art of glass cutting was in bloom. Antoni van LEEUWENHOEK (1632 - 1723) is often referred to as the inventor of the microscope. Simple microscopes probably existed before him, but he perfected the construction of single-lens microscopes (actually these microscopes were extreme magnifying glasses) and, above all, he made important discoveries with the help of his more than 400 microscopes.
Leeuwenhoek (picture left) succeeded in grinding lenses whose focal length was in the range of 1 mm, so that their magnification had a value of approx. 200. In addition, he equipped his apparatus with precision mechanics that allowed focusing on the specimen and correct positioning of the specimen (middle picture). The picture on the right shows how such an early microscope was used.

Leeuwenhoek was the first to find in his dental plaque bacteriawhich he depicted in the adjacent sketch. The importance of bacteria for mankind could not be foreseen at that time. In the course of time, however, the microscope has become an important tool in the discovery of pathogens.
Leeuwenhoek discovered the peripheral blood circulation in the fine capillaries and was thus able to explain the connection between the arterial and the venous blood circulation, a hitherto unsolved problem for medical professionals.
Leeuwenhoek's most spectacular scientific act, however, was the discovery of human spermatozoa and the sexual reproduction of all living things. In addition to that of many other animals, he meticulously observed the sexual behavior of the fleas and the developmental steps from the fertilized egg to the fully developed flea. He did not shy away from carrying these research objects around in his pocket and feeding them with his own blood.
(from: Deutsches Museum, Munich: Departure into the micro world)


There are limits to reducing the focal length of a lens. The lens would be too thick and the aberrations too large. As early as Leeuwenhoek's time, attempts were therefore made to increase the magnification with the help of two lenses. English physicist Robert Hooke (1635 - 1703) reported in his famous work Micrographia about a two-lens microscope that was very similar to today's, but with which the focus was still causing major problems. The Hook microscope was very faint. To illuminate his preparations, Hooke therefore used an oil lamp, the light of which he concentrated with a water-filled glass ball that acted as a lens. Hooke also examined a bottle cork with his microscope (right picture). He was the first to discover that plant tissue was made from Cells exists and thus laid the basis for cell theory (cytology).

In the centuries that followed, the optical and mechanical quality of light microscopes was constantly improved. Today they represent an indispensable tool in many areas of science.
However, there are physical limits to magnification with light (distances in the range of the wavelength of light, i.e. approx. 600 nm, can still be separated). Recently, so-called electron microscopes have been used to achieve even higher magnifications. With completely new techniques (scanning tunnel microscope) it is now possible to depict atoms.

If you are interested in a more detailed description of the historical development of the microscope, then inform yourself on the following page (it contains not only information on the light microscope, but also on further electronic developments that go far beyond the content of the class level): http: / /www.amuseum.de/mikoskopie/mikoskopvortrag4.htm