A Brief History
On September 17, 1683, Dutch scientist Antonie van Leeuwenhoek presented a paper to the Royal Society (The President, Council and Fellows of the Royal Society of London for Improving Natural Knowledge) containing a description of the first scientific recognition of microbes/protozoa, a living thing he referred to as “animalcules” (single celled organisms). Although van Leeuwenhoek had designed his microscope himself and is known as “The Father of Microbiology,” he was definitely not the inventor of the microscope. In fact, exactly who is the inventor of this highly important contribution to science is not agreed upon by historians.
The idea of lenses, clear objects (today normally glass) to focus light in order to magnify images was probably known a few thousand years ago, including the effect of water on light, the first practical use of image magnification came about in the 13th Century with the invention of eyeglasses. The first known patent of a telescope in 1608 belongs to Hans Lippershey of the Netherlands, employing the familiar layout of telescopes and microscopes by using 2 lenses in tandem, an objective lens (nearest the object observed) and an eyepiece lens (nearest the user’s eye). Inventors soon discovered curved mirrors could also be employed in the manufacture of telescopes. Soon after the invention of the telescope to magnify distant objects, it was realized using the same 2 lens arrangement could also be used to greatly enhance the effectiveness of a magnifying glass for viewing very small objects, et voilà , the microscope was invented! For the first time humans could see the world of objects too small to observe with the naked eye.
The Netherlands in the 17th Century was a hotbed of experimentation and discovery in the field of lenses, and the manufacture of eyeglasses and spectacles in this region fed the budding science of magnification. Suspects in the lineup of potential inventors of the microscope include the previously mentioned Hans Lippershey, Zacharias Janssen (with a claim as early as 1590), and fellow Dutchman Cornelis Jacobszoon Drebbel (inventor of the first navigable submarine). Drebbel, working in London, England, reportedly had a microscope as early as 1619. Famous Italian scientist and astronomer Galileo Galilei is also said to have realized the close up potential of his telescope modified to perform as a microscope around 1610, and his invention was reported on by Giovanni Faber who called the device a “microscope,” giving us the modern term.
Microscopes were originally more of a curiosity than a scientific tool, and serious use of the microscope to study micro-anatomy did not begin in earnest until 1644. Using microscopes to study organic and inorganic items took off in the latter half of the !7th Century, and van Leeuwenhoek pioneered the study of micro-organisms. Van Leeuwenhoek studied blood cells and discovered spermatozoa among his other studies. By 1676, van Leeuwenhoek had reported his findings about micro-organisms (prior to his report to the Royal Society). The importance of microbes to their place in the health of people and macro-organisms would not be realized for many decades to come.
Specimens for examination by microscopes were originally illuminated by ambient light or by candles, and then by the use of mirrors. Not until 1893 did August Köhler apply electric lighting to illuminate microscope specimens in a manner to optimize the observation of the specimen (Köhler illumination). Other methods of optimizing illumination including the use of light to provide contrast were developed in the 20th Century. Also developed in the 20th Century was an entirely new sort of microscope, the Electron Microscope. German scientist Ernst Ruska invented the electron microscope in 1931, a device he called the “transmission electron microscope” (TEM). This rudimentary form of using an electron beam to create an image instead of light magnification was improved upon by Max Knoll, also a German scientist, in 1935, with the invention of the scanning electron microscope (SEM). Early use of TEM type electron microscopes became commercially available during the 1930’s, but the SEM variety was limited to government sponsored research only and did not become available for commercial use until 1965. The electron method created images in vastly superior clarity and detail compared to optic microscopes and enabled researchers to view far smaller objects and details. It was the electron microscope that enabled scientists to study viruses, organelles too small to be observed in optical microscopes. Although the idea of viruses being a germ smaller than bacteria was theorized and a body of work developed about them between the late 19th Century and the 1930’s, it was not until Ruska and Knoll used an electron microscope to view them had any human ever seen an image of a virus.
Other modern electronic microscope devices have been developed, including Fluorescence microscopes (late 20th Century) and X-Ray microscopes (1970’s), as well as a highly advanced form of optical microscope called Super resolution microscopes have been developed starting in the 21st Century, a notable advancement being the stimulated emission depletion (STED) microscope, which provides an image with nearly the resolution of electron microscopes. Other assorted types of modern microscopes include scanning probe and acoustic microscopes.
Questions for Students: Have you ever owned your own microscope? Did you use microscopes in science class in school? Have you looked at photographs of electron microscope images? What do you think is the smallest object that can be currently observed by a microscope? (Click the link for the answer.)
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For more information, please see…
Headstrom, Richard. Adventures with a Microscope. Dover Publications, 2012.
Hogg, Jabez. The microscope : its history, construction, and application, being a familiar introduction to the use of the instrument and the study of microscopical science (1871). Amazon Digital Service, 2015.
The featured image in this article, a drawing by naturalist Henry Baker from 1756 of microscopes owned by Antonie van Leeuwenhoek, is in the public domain in its country of origin and other countries and areas where the copyright term is the author’s life plus 100 years or less.