Sarah Waddles age 11, of Cleveland, Ohio, oar her question:
Who invented the microscope?
A simple microscope is a lens of glass, thick in the middle and thinner at the edges. This glassy shape plays tricks with beams of light. It bends them at angles and, when we look through such a lens, these bending light rays enlarge what we see. This gadget is such a good idea that it was discovered in ancient times, perhaps by accident. Maybe soon after the invention of glass some one discovered that things look bigger through a glassy blob.
We know that there were magnifying glasses about 600 B.C, because Euclid, who set forth the rules of .geometry, described such a curved reflecting surface. In 65 B.C. Seneca of Rome reported that a glass globe filled with water could be used to enlarge tiny things which often escape unnoticed. Around 150 A.D. the ,great astronomer Ptolemy looked into glass lens as a means of magnifying.
Around 1235, the magnifying lens was put to a very practical purpose. The English scientist Roger Bacon invented spectacles. At the end of the 15th century, the artist and scientist Leonardo da Vinoi stressed the importance of using lenses to study small objects. All these microscopes were single, simple lenses and people were gradually learning how to use them. We still use a simple magnifying glass in a microscope and some simple microscopes have two lenses placed close together.
The compound microscope uses two lenses, one at each end of a tube. The simple microscope, even when there were two lenses, magnifies the image only once. The compound microscope magnifies the magnified image. It was invented in 1590 by Zacharius Janssen and his son Lans.
This was a mighty step forward, but it was only one step in the long, long development of the microscope. New methods are still being discovered that make better and more accurate microscopes.
A modern compound microscope is a fine and expensive instrument well worth owning. 'The object to be magnified is placed on a stage under the tube. If the specimen is mounted on a transparent slide, it is lighted from below. If it is an opaque piece of rock, the light is directed to fall on it from above. You look down through the tube and the image comes to you through two separated lenses. There are two wheels to bring the small miracle into proper focus. The magnified image can be photographed. The enlarged image may also be reflected onto a screen.
A number of different microscopes have been developed for different jobs. Ultra violet rays streams of electrons or ions reveal even smaller miracles, though the results must be seen ran photographic plates. In some microscopes, two eyepieces are used to compare specimens. This is the comparison microscope used so often in police work. It can tally the bore marks on a pair of bullets. That is how the homicide men discover whether the bullet was fired from your gun or from someone else’s.