Optical Characteristics of a Leeuwenhoek
Correlated images of a section cut by Leeuwenhoek in 1674 reveal the optical quality of the single lens.
Here we see a section of pith from Sambucus nigra (elder) imaged through four microsopical systems:
[Top left] View with Original Leeuwenhoek
[Top right] Modern Leitz optical microscope (light-ground).
[Bottom Left] Modern Leitz optical microscope (dark-ground).
[Bottom right] Cambridge Stereoscan electron microscope image.