Our eyes can only perceive an object when it appears larger or smaller depending on its distance from our eyes. Nevertheless, when something is brought closer to the eye than about 10 inches, we cannot distinctly recognize the object because we cannot focus on it sharply. The human eye has limited accommodative power or its ability to change focus, because if we do we would not need microscopes. Anton van Leeuwenhoek (1632-1723) invention was the earliest simple microscope which is a byproduct of research by those brilliant minds such as Galileo, Janssen and Kepler. His microscope was very simple, but his talent at grinding lenses makes it more advanced compare to other compound microscopes used during his time. Compared to modern microscopes, his device was extremely simple using only one lens that served as eye piece of the object. The eye piece is mounted in a tiny hole in the brass plate that serves as the body of the instrument.

The specimen was placed on the sharp spot that sticks up in front of the lens and using the two screws the position and its focus could be adjusted. The entire instrument was only 3-4 inches long, and since the device needs a good lighting it should be held up close to the eye. By using the tiniest pieces of glass and hand polish it to a very short radius of curvature he could magnify it up to 200x. A small piece of glass in those times had fewer imperfections so most likely it can’t mess up the reflection of the object. But on the other hand, the complexity of using such instrument is its ability to focus. This handicap of limited focus can be overcome artificially placing the lens in front of the eye. By adjusting the space between the eye and the lens, the image will be seen as visibly as if it were about 10 inches from the eye but magnified as if it were much closer. This simple lens made it possible for the eye to focus on a very near object, the higher the power of the lens the closer it must be in the eye. Although the magnification is only limited to about 20x we cannot deny it’s contribution to the world of microscopy.

To see into the universe of the tiniest object is like going into to the world of endless possibilities. Examining the microscopic details of living things is one of the earliest uses of microscopes. Because of Leeuwenhoek’s craving of knowledge and by the help of his invention he was able to study the structure of tissue, bacteria, sperm cells, microscopic nematodes and rotifers, protozoa in water and much more. He’s the one who recognized minute blood carrying capillaries, helping to complete the composition of circulation. His discoveries and researches, which were widely disseminated, opened up an entire world of microscopic life to the awareness of scientists. Simple microscopes were the best of its kind and this unlikely scientist constructed over 500 microscopes that were considered superior to any microscopes in his time. Only nine out 500 have survived to the present day.