History of the Microscope

Humans have always had a desire to explore the world around them. The only limitation they had was the capability of the naked eye. Over time, new inventions have been created to expand the range of visibility. One of the most important and influential discoveries was the microscope.

The first microscope was invented by father and son eye glass makers, Zaccharius Janssen and Hans Janssen. They put multiple lenses in a tube, and discovered that specimens appeared much larger than normal. This tube was the predecessor to the compound microscope and the telescope. The magnification rates of the Janssen microscopes were between 3X and 9X.

The microscope was vastly improved by an apprentice in Holland named Anton van Leeuwenhoek. Leeuwenhoek used magnifying glasses to examine the thread count in cloth. He began to grind these lenses so that the curvature was greatly increased, giving magnification rates of up to 270 diameters. These single lens microscopes were the best of the time period, and led to him observing bacteria, protozoans, yeast plants, and blood circulation. His findings were sent to the Royal Society of England and the French Academy. However, he kept his method of crafting these lenses a secret, which died with him.

In 1660, Robert Hooke improved upon compound microscopes. His research was compiled in his book, Micrographia, and earned him the title of English father of microscopy. He confirmed the discovery of tiny organisms in water made by van Leeuwenhoek. He also examined a thin slice of cork, and found that it was comprised of air pockets. Dubbing these air pockets “cells,” the term has remained to this day.

Throughout the 18th century, more advances were made to the compound microscope. Lenses using two different types of glasses were employed, reducing visible blur, known as the “chromatic effect.” Microscope slides and stages were invented to secure the specimen and improve the quality of the image. New sampling techniques were also used, including dying the specimen as well as chemical and water solutions.

In 1872, Ernst Abbe wrote a mathematical formula known as the “Abbe Sine Condition.” This formula determined the best resolution in microscopes that was possible at that time. During the middle of the 19th century, mass production of microscopes began in Europe. Microscopes were growing more affordable, and easy to use. In America, Charles A. Spencer developed fine quality microscopes that gave magnifications up to 1250 diameters in normal light and 5000 diameters in blue light.

In 1930, the electron microscope was born, invented by Max Knott and Ernst Ruska. Instead of using light, these microscopes use sped up electrons within a vacuum to view incredibly small objects, such as an atom. However, no living things can survive the vacuum, so living cells and tissue cannot be observed with an electron microscope.

Advances in microscopes are being made frequently. They are evolving at an incredible rate, due to the new technologies available. The history of the microscope shows what can be accomplished by curiosity, ingenuity, and necessity.

Like this article? History of the Microscope