The first electron microscope was invented. Microscopes
A microscope (from the Greek micros - small and skopeo - I look) is a device that allows you to obtain an enlarged image of objects and structures that are inaccessible to the human eye.
In the practice of medical and biological research, methods of light and electron microscopy are used.
Light microscopes can magnify an object as small as 0.5 microns with a resolution of object elements down to 0.1 microns by more than 1,500 times, and electron microscopes can magnify by 20,000 times.
Light microscopy is based on the laws of geometric optics and the wave theory of image formation; natural or artificial light sources are used as illumination.
History milestones:
Simple microscopes appeared in the 17th century. The Dutch scientist A. Leeuwenhoek achieved great success in their production.
In 1609-1610 a complex microscope was built by G. Galileo (1564-1642).
In 1846, the German mechanic Karl Zeiss (1816-1888) opened a workshop and a year later began manufacturing microscopes. Karl Zeisse successfully used the discoveries of physics professor Ernst Abbe, who later became his full-fledged partner, in the activities of his company.
Theoretical and practical work Ernst Abbe (1840-1905), Otto Schott (1851-1935) and August Köhler (1866-1948) determined the direction of development and principles for constructing optical systems of modern microscopes.
Electron microscopy produces electron-optical images using a stream of electrons. The construction of the image is based on the laws of geometric and wave optics, as well as the theory of electromagnetic fields. Electron microscopy makes it possible to study objects whose dimensions are beyond the resolution of a light microscope (less than 0.2 microns), and is used to study viruses, bacteriophages, the fine structure of microbial cells and other submicroscopic objects, as well as macromolecular structures.
The electron microscope appeared in the late 30s. During these years, the German company SIEMENS began serial production of electron microscopes. In 1940, at the State Optical Institute named after. S. I. Vavilova (Leningrad) created the first domestic electron microscope with a magnification of up to 10,000 x and a resolution of about 400 A.
Electron microscopes are mainly used in research laboratories and their cost starts from two to three million rubles.
Microscopes. How it all began…
Starting from this issue, the newspaper presents a column dedicated to the history of the development of microscopy, which is a necessary condition existence of cytology.
The invention of this device, important for all biology, was due, first of all, to the influence of the development of optics. Some optical properties of curved surfaces were known to Euclid (300 BC) and Ptolemy (127-151), but their magnifying ability was not found practical application. In this connection, the first glasses were invented by Salvinio deli Arleati in Italy in 1285. XVIcentury, Leonardo da Vinci and Maurolico showed that small objects are best studied with a magnifying glass. At the same time, in the Netherlands, hereditary opticians Zachary and Hans Jansen in 1590 mounted two convex lenses inside one tube, i.e., actually creating the first microscope and laying the foundations for the creation of complex microscopes.
The Jansen microscope is shown in Fig. 1. Its increase ranged from 3 to 10 times. Each subsequent microscope has been significantly improved. In this period (
XVIc.) Danish, English and Italian research instruments gradually began to spread, laying the foundation of modern microscopy.
With the improvement of optics in 1674, Antonie van Leeuwenhoek produced lenses with magnification sufficient to make simple scientific observations. It is worth noting that in
XVIIV. Along with Leeuwenhoek, several scientists were involved in microscopy. Thus, Galileo (1610) constructed a microscope by combining lenses in a lead tube. Descartes in his book "Dioptrics" (1637) described a complex microscope composed of two lenses - a plano-concave (eyepiece) and
biconvex (lens).
In Fig. 2 shows a Leeuwenhoek microscope dating back to the late 1890s. The dimensions of his instruments were relatively constant and were approximately 2 inches long (1 inch = 2.52 cm) and 1 inch wide. The main body of these microscopes consisted of 2 flat and thin metal (usually brass) plates riveted together, between which were placed small biconvex lenses with a possible magnification of 70 to 250 times depending on their quality.
Leeuwenhoek devoted a lot of time to the production of lenses for his microscopes, and it was he who created lenses with the highest magnification and resolution of all known microscopes of that time.
It is worth noting that it was Leeuwenhoek’s microscopes that were the first to be brought to Russia on the instructions of Peter I. During his stay in Delft, Peter Iinvited Leeuwenhoek to his yacht, who demonstrated the microscopes he had improved and showed a number of experiments. After which the microscopes were purchased and sent to Russia. Domestic microscopes were first designed in XVIIIcentury. About them and others important events in the history of microscopes during XVIIIcentury the story will be in the next issue of the CIS.
Literature:
1. Museum of Microscopes - electronic database (http://microscopy.fsu.edu/primer/museum/index.html).
2. E. de Robertis, V. Novinsky, F. Saez General cytology. M., 1962
3. G.I. Roskin, L.B. Levinson Microscopic technique. M., 1957.
Essay prepared by A. Solovyov
An optical instrument with one or more lenses to produce magnified images of objects not visible to the naked eye. Microscopes can be simple or complex. A simple microscope is a single lens system. A simple microscope can be considered an ordinary magnifying glass - a plano-convex lens. A compound microscope (often called simply a microscope) is a combination of two simple ones. A compound microscope provides greater magnification than a simple one and has greater resolution. Resolution is the ability to distinguish details of a sample. An enlarged image in which details are indistinguishable provides little useful information. A complex microscope has a two-stage design. One system of lenses, called an objective, is brought close to the sample; it creates a magnified and resolved image of the object. The image is further magnified by another lens system called an eyepiece, which is placed closer to the viewer's eye. These two lens systems are located at opposite ends of the tube.
TYPICAL MICROSCOPE with one eyepiece and two interchangeable objectives on a turret. Magnification ranges from 100 to 1000. 1 - tripod stand; 2 - hinge for tilting; 3 - tube holder; 4 - micrometer adjustment knob; 5 - coarse adjustment knob; 6 - eyepiece; 7 - eyepiece holder; 8 - tube; 9 - turret head; 10 - lenses; 11 - object table; 12 - condenser; 13 - lower holder; 14 - mirror
> History of the creation of the microscope
It is impossible to determine exactly who invented the microscope. Dutch spectacle maker Hans Jansen and his son Zacharias Jansen are believed to have invented the first microscope in 1590, but this was a claim made by Zacharias Jansen himself in the mid-17th century. The date, of course, is not exact, since it turned out that Zachary was born around 1590.
It is believed that the next significant improvement of the microscope was made by the Englishman R. Hooke 75 years later. At the same time, the contribution made to the development of microscopy by the famous Italian Galileo Galilei is completely overlooked... When rumors spread in 1609 that an amazing device had appeared in Holland, Galileo began to think about it. It took the scientist just a day to understand the essence of the matter and build a sample of his own design. New area Galileo was fascinated by research, and in 1612, experimenting with lenses, he independently, independently of Jansen, invented a microscope. And he not only invented, but also began to manufacture these devices to give to noble patrons.
He developed the "occhiolino", or compound microscope with convex and concave lenses, in 1609. Galileo presented his microscope to the public at the Accademia dei Lincei, founded by Federico Cesi in 1603. Francesco Stelluti's image of three bees was part of the seal of Pope Urban VIII and is considered the first published microscopic symbol (see Stephen Jay Gould, The Lying stones of Marrakech, 2000).
Thus, Galileo has the honor of, if not the first, then at least the independent invention of the microscope and its application to the study organic world. But he himself did not continue work in this new and very promising area of research, preferring the study of the sky using a telescope, which was more akin to his genius.
Ten years after Galileo, Cornelius Drebbel invents new type microscope with two convex lenses. Christiaan Huygens, another Dutchman, invented a simple two-lens eyepiece system in the late 1600s that was achromatically adjustable and therefore a huge step forward in the history of microscope development. Huygens eyepieces are still produced today, but they lack field of view width and the eyepiece placement is uncomfortable on the eyes compared to modern wide-field eyepieces. In 1665, Englishman Robert Hooke designed his own microscope and tested it on a cork. As a result of this research, the name "cells" was born. Anton Van Leeuwenhoek (1632-1723) is considered to be the first to bring the microscope to the attention of biologists, despite the fact that simple magnifying lenses had already been produced since the 1500s, and the magnifying properties of water-filled glass vessels were mentioned by the ancient Romans (Seneca) . Handcrafted, Van Leeuwenhoek's microscopes were relatively small products with a single, very strong lens. They were inconvenient to use, but they made it possible to examine images in great detail only because they did not take over the shortcomings of a compound microscope (several lenses of such a microscope doubled the image defects). It took about 150 years of development in optics for a compound microscope to be able to produce the same image quality as simple Leeuwenhoek microscopes. So, although Anton Van Leeuwenhoek was a great master of the microscope, he was not its inventor, contrary to popular belief.
Microscope(from Greek - small and looking) - optical instrument to obtain enlarged images of objects (or details of their structure) invisible to the naked eye.
It is impossible to determine exactly who invented the microscope. The Dutch spectacle maker Hans Jansen and his son Zacharias Jansen are believed to have invented the first microscope in 1590, but this was a claim made by Zacharias Jansen himself in the mid-17th century. The date is, of course, not exact, as it turns out that Zechariah was born around 1590. Another contender for the title of inventor of the microscope was Galileo Galilei. He developed the "occhiolino", or compound microscope with convex and concave lenses, in 1609. Galileo presented his microscope to the public at the Accademia dei Lincei, founded by Federico Cesi in 1603. Francesco Stelluti's image of three bees was part of the seal of Pope Urban VIII and is considered the first published microscopic symbol. Ten years later, Galileo Cornelius Drebbel invents a new type of microscope, with two convex lenses. Christiaan Huygens, another Dutchman, invented a simple two-lens eyepiece system in the late 1600s that was achromatically adjustable and therefore a huge step forward in the history of microscope development. Huygens eyepieces are still produced today, but they lack a wide field of view and the eyepiece placement is uncomfortable on the eyes compared to modern wide-field eyepieces. In 1665, Englishman Robert Hooke designed his own microscope and tested it on a cork. As a result of this research, the name "cells" was born. Anton Van Leeuwenhoek (1632 -1723) is considered the first who managed to attract the attention of biologists to the microscope, despite the fact that simple magnifying lenses had already been produced since the 1500s, and the magnifying properties of glass vessels filled with water were mentioned by the ancient Romans (Seneca). Handcrafted, Van Leeuwenhoek's microscopes were very small products with one very strong lens. They were inconvenient to use, but they made it possible to examine images in great detail only because they did not take over the shortcomings of a compound microscope (several lenses of such a microscope doubled the image defects). It took about 150 years of development in optics for a compound microscope to produce the same image quality as simple Leeuwenhoek microscopes. So, although Anton Van Leeuwenhoek was a great master of the microscope, he was not its inventor, contrary to popular belief.
A microscope has mechanical and optical parts. The mechanical part is represented by a tripod (consisting of a base and a tube holder) and a tube mounted on it with a revolver for attaching and changing lenses. The mechanical part also includes: a stage for the preparation, devices for fastening the condenser and light filters, mechanisms built into the tripod for coarse (macro-mechanism, macro-screw) and fine (micro-mechanism, micro-screw) movement of the stage or tube holder.
The optical part is represented by lenses, eyepieces and a lighting system, which in turn consists of an Abbe condenser located under the object stage and a built-in illuminator with a low-voltage incandescent lamp and transformer. The lenses are screwed into the revolver, and the corresponding eyepiece, through which the image is observed, is installed on the opposite side of the tube.
