The Microscope

By: Brianna Carmon

The Invention of Glass Lenses

The Romans experimented with different types of glass. A type of glass that they experimented with was thick in the middle and thin on the edges. They discovered that if you hold the "lenses" over an object it looks larger than it should be. They also discovered that you can focus the ray of the sun with with one of the lenses and start a fire. Hey called them magnifiers or burning glasses. The word lense originated from the word lentil, and also the shape of a lentil bean. Theses lenses were not used until the end of the 13th century when spectacle makers were producing glasses.

The Invention of Glass Lenses

The early simple microscopes which were magnifying glasses had one power 6x to 10x. They were called flea glasses because the lenses were common to look at fleas and other tiny insects. Around the year 1590, two Dutch spectacle makers Zaccharias Janssen and his father Hans started experimenting with these lenses and created a compound microscope. They put several lenses in a tube and the object near the end of the tube appeared to be enlarged, much larger than any simple magnifying glass.

The Invention of the Glass Lenses

Anthony Leeuwenhoek became very interested in lenses while woring with magnifying glasses in a dry goods store. By grinding and polishing he was able to make small lenses. These rounder lenses produced greater magnifications, his microscopes were able to magnify up to 270x. He used the lenses to count threads in woven cloth. He was also able to see bacteria, yeast, blood cells and many tiny animals swimming about in a drop of water. Companies in Germany such as Zeiss and an American company founded by Charles Spencer began producing fine optical instruments.