Giovanni Battista Amici

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Giovanni Battista Amici, lithograph by Rudolf Hoffmann , 1856
Giovanni Battista Amici, 1874

Giovanni Battista Amici (born March 25, 1786 in Modena , † April 10, 1863 in Florence ) was an Italian manufacturer of optical instruments of outstanding quality. In addition to developing and improving his devices, which were widely used in many European countries, he also made important botanical , zoological and astronomical studies with his microscopes and telescopes . Giovan or Batista and Giambattista can also be found as the first name.

After studying mathematics in Bologna , which he completed in 1807 at the age of 21, he worked in Modena before moving to Florence in 1831. At a young age he became famous as a manufacturer of optical devices. He introduced improvements that are still used in light microscopy today.


Childhood, education and positions in Modena

Amici was born on March 25, 1786 as the son of the civil servant Giuseppe Amici in Modena, which belonged to the Duchy of Modena . Already in his early youth he showed great interest in mathematics and eventually became a student of the algebraic Paolo Ruffini , who was a lecturer in Modena. In 1806 he married Teresa Tamanini, with whom he had three children: Vincenzo (* 1807), Elena (* 1808) and Valentino (* 1810).

His studies in mathematics, mechanics and hydrodynamics were so successful that instead of two years, he was admitted to the final exam at the University of Bologna after one year . In 1807, at the age of just 21, he graduated as an engineer-architect and in the same year became a professor of geometry and algebra at the University of Modena . When the university reopened in 1815 after the Napoleonic Wars , Amici was appointed professor of geometry, algebra and trigonometry in the philosophy faculty.

With substantial financial support from his father and his wife, Amici had set up a laboratory workshop in his house in Modena, where, in addition to teaching at the university, he improved optical devices or built new ones based on his own ideas. He also used his telescopes and microscopes for his own observations. He quickly became known internationally. In recognition of his services, he was released from his teaching duties in 1825 or 1826 and appointed "the Ministry of Physical and Mathematical Sciences advising professor" so that he could devote himself more to his research. The only obligation was to report annually on advances in physical-mathematical sciences.

After the revolutionary movement in Modena, he was made chairman of the public education system by the provisional government in 1831. However, the count returned after a few months and Amici had to justify himself.

Florence and Pisa

Memorial plaque for Amici at the Palazzo Demidoff-Amici in Florence.

At the end of 1831 Amici succeeded Jean-Louis Pons as an astronomer at the Museum of Physics and Natural History in Florence (Museo di storia naturale), where he was supported by his son Vincenzio (later professor of mathematics in Pisa). Nominally he became professor of astronomy at the University of Pisa . The cities, which are about 80 km apart, both belonged to the Grand Duchy of Tuscany . Amici moved to Florence, where he helped intensively to turn the museum into an active study and research center. Soon he also took over the management of the astronomical observatory, where he particularly promoted the equipment. Wealthy and as a personal friend of the prince, the best working conditions arose for him.

Amici also moved his optics workshop to Florence and he and a few workers continued to produce microscopes that were delivered all over Europe. His accounting book shows that between 1817 and 1863 he delivered more than 100 large and around 200 medium and small microscopes, plus 270 drawing chambers, around 10 astronomical telescopes, around 10 prism telescopes and 150 other optical devices. He also continued his microscopic observations. When the first all-Italian association of scientists met in Pisa in 1839, Amici was one of its representatives. This association contributed to the Italian unification movement through some national scientific congresses .

In 1846 or 1847, when a typhus epidemic broke out during a summer stay in the family's country house in Modena, all female family members were killed.

In 1848 Amici was appointed member of the constitutional government of Tuscany. In the Provisional Government of Modena he took on a task in connection with the war against the Austrians. When the Grand Duke of Tuscany was deposed in 1859, Amici was also dismissed from all academic positions, to his chagrin. However, he was made an honorary professor of astronomy and also tasked with microscopic research at the Florentine Museum. He held this position until his sudden death in 1863 at the age of 77. Amici was scientifically active until his death. Two days before his death he took part in microscopic observations.


Amici began to occupy himself with the construction of optical devices, because during his university studies the quality of the existing devices did not seem sufficient to him. He later formulated his quality standards as follows:

“I do not take on orders that take away the freedom to change the shape of the instruments in all those parts as I feel that I think can be improved. If an instrument is to bear my name, I want it to be made according to the principles that seem most perfect to me. "

The well-known German botanist Hugo von Mohl wrote in an obituary about the quality of Amicis instruments:

"Even if the metalwork of his instruments left much to be desired in many cases, the optical part of them, on the other hand, was executed in the more perfect manner, but above all the majority of them were characterized by the new ideas on which they are based."

Microscope construction

Scheme of an achromatic lens according to Amici with a single front lens, from Czapski (1904).
Amici compound microscope from around 1827 from his workshop in Modena.
Amici microscope on a GDR postage stamp. The imprint states “Modena 1845”, but Amici moved to Florence in 1831.

Amici began his career as an instrument maker with the improvement of catadioptic microscopes, i.e. those that magnify with the help of mirrors and not with glass lenses. In 1812 he received an award in Milan for one of his models. After various further developments, he published the results he had achieved in this area in 1818. After he recognized the limits of catadioptic microscopes, he subsequently devoted himself to the more widely used compound dioptic microscope, which generates magnification with glass lenses. Even today, this is the most common type of microscope.

Amici introduced two major innovations in the construction of light microscopes that have survived to this day: a single front lens with a short focal length, flat towards the specimen, and immersion .

In Amici's time, achromatic microscope objectives, i.e. those that were corrected for color errors, had three pairs of lenses. One of them was facing the preparation. In 1827, Amici replaced this with a single, hemispherical lens. In a manuscript from 1855 he described his reasons for this step: The pair of lenses was quite large, so that no short focal lengths and thus only a limited magnification was possible. A single lens with a short focal length produced a color error, but he corrected it within the other two lens pairs. He got the flint glass with high dispersion required for this through Airy from Faraday . The shorter focal length enabled a larger opening angle and thus a better numerical aperture . The resulting image enhancement is seen as essential to many microscopic discoveries of the 19th century.

From 1847 Amici first used immersion with water between the lens and the cover glass. He was not the first to do this, but through his extensive experiments and the lenses he made for many researchers, it became known to a larger group of users. For example, a manuscript of his from 1849 describes a microscope with water immersion for Franciscus Cornelis Donders in Utrecht. Subsequently, Amici also manufactured immersion objectives for liquids with a higher refractive index , such as glycerine and various vegetable oils. The delivery of several dozen oil immersion objectives to European customers has been proven. The high quality of his lenses is proven not least by the richness of detail in the observations he himself made and published on plant parasites and striated muscles .

Astronomical devices and observations

At the age of 24, in 1810, Amici built a reflecting telescope with an aperture of 155 mm and a focal length of 2.4 m. It was considered by the astronomers of the Osservatorio Astronomico di Brera in Milan to be equivalent to that of Wilhelm Herschel . On August 15, 1811, Amici received the large gold medal of the royal institute in Milan at a solemn meeting.

He made a telescope 28.8 cm in diameter and 6.28 meters in length, and in 1812 a telescope of a new design with a concave mirror and a plane mirror drilled through in the center , the diameter of which was 30 cm and which was 6.5 m long. His device for measuring the light intensity of an astronomical object by means of double images deserves special attention .

Amici used his devices to study binary stars and the moons of Jupiter . With a micrometer he had developed , he was able to make precise determinations of the polar and equatorial diameters of the sun .

Microscopic observations

Amici's first publication with microscopic observations appeared in 1818, at the same time as his work on the mirror microscope, which he used for these early observations. She treated the plasma flow within a cell described by Bonaventura Corti in 1774 in aquatic plants using the example of common candy algae ( Chara vulgaris ). His improved microscopes made it possible to visualize leukoplasts and chloroplasts . He describes his observations in detail, not without mentioning that he has already presented them to various famous personalities, including Archduke Maximilian of Austria , Archduke Leopold of Tuscany and Prince von Metternich.

Blossom of Portulaca oleracea

A second plant physiological work followed in 1823. Amici actually wanted to find out whether plasma currents only occur in aquatic plants or also in land plants. In 1821, during his investigation, he accidentally observed the breaking of a pollen grain and the emergence of the pollen tube in purslane (Portulaca oleracea) . Recognizing the importance for the reproduction of the seed plants , he devoted himself to this phenomenon in the following years and made a major contribution to refuting incorrectly interpreted observations, especially by Matthias Jacob Schleiden , and to laying the foundation for an understanding of fertilization in flowering plants . This earned him violent attacks from Schleiden at times. Amici described the penetration of the pollen tube into the ovule through the micropyle (1829) and the development of the embryo from a 'vesicle' already existing in the embryo sac , the egg cell , after contact with the pollen tube. In 1846 he finally published his studies on the fertilization of orchids , which decided the dispute with Schleiden. Hugo von Mohl judged this work in an obituary for Amici in 1863:

"Amici ... also followed the other processes in the orchid egg, the presence of the germinal vesicle before fertilization, the origin and development of the embryo from it, in such a complete way that the later examinations only confirm otherwise, but hardly an important one Could deliver additional. In Amici's work, the entire fertilization process of a plant, from the pollination of the stigma to the full development of the embryo in all stages, was given a correct and coherent description for the first time. It was the model for all later investigations and at the same time the fatal blow of Schleiden's heresy. "

In the same obituary, von Mohl reported that in response to Schleiden's attacks, Amici sent him one of his microscopes so that he could see for himself with better technology.

Further botanical work dealt with stomata , the palisade parenchyma , the cell membrane and the connections between tissue cells. Microbiological studies treated Oscillatoria and pathogens from roses , vines , mulberry trees , wheat and silkworms . Amici published few zoological studies. His work on striated muscles from 1858, in which he summarized observations since 1828, deserves special mention . Since that year he has been using fly muscle fibers as test objects to assess the quality of his lenses and found that these were not constructed according to the doctrinal opinion. Over the years he also examined fibers from other animals and humans. Among other things, he discovered that muscle fibrils are made up of longitudinally oriented filaments, about a hundred years before myofilaments could be made visible with an electron microscope .


Amici was made an honorary member of over thirty scientific societies, including the Italian ( Società Italiana per il Progresso delle Scienze ), the Pontificia Accademia Romana dei Nuovi Lincei , the Royal Astronomical Society , the Royal Academy of Medicine in Paris and the Imperial Society of Natural Sciences in Moscow . The Berlin University made him an honorary doctorate in medicine and surgery in 1860.

Since 1836 he was a corresponding member of the Royal Prussian Academy of Sciences .

The lunar crater Amici is named after him, as is the minor planet (3809) Amici of the asteroid belt , which was discovered in 1984 at the Osservatorio San Vittore in Bologna.

In 1979 the authors Alberto Alberti, Gerhard Hentschel and Giovanna Vezzalini named a mineral in honor of Amici as Amicit (English: Amicite). They discovered the new zeolite mineral on Höwenegg , an extinct volcano near Immendingen in southern Baden-Württemberg. The formula is K 2 Na 2 (Si 4 Al 4 O 16 ) · 5H 2 O.

Amici publications

Amici has published over fifty scientific papers. Only a selection is given here.

  • The microscopi catadiottrici . Presented on March 5, 1818. In: Memorie di Matematica e di Fisica della Società Italiana delle Scienze residente in Modena . tape XVIII , 1820, p. 107–124 ( Italian online version [PDF]).
  • Osservazioni sulla circolazione del succhio nella Chara . Presented on August 10, 1818. In: Memorie di Matematica e di Fisica della Società Italiana delle Scienze residente in Modena . tape XVIII , 1820, p. 183–202 ( online at the Biodiversity Heritage Library ).
  • Osservazioni microscopiche sopra varie piante . Presented on March 22, 1822. In: Memorie di Matematica e di Fisica della Società Italiana delle Scienze residente in Modena . tape XIX , 1823, p. 234–286 ( Version 1 on Google Books , Version 2 on Google Books , with different excerpts from the figures).
  • Sulla fecondazione delle orchide . Presented at the 8th meeting of Italian scientists on September 17, 1846. In: Giornale botanico italiano . Volume 2, part 1, volume 1 , 1846, p. 237–248 ( online at the Bayerische Staatsbibliothek ). Contemporary German translation (without images): About the fertilization of orchids . Translator: Hugo von Mohl. In: Botanische Zeitung . tape 5 , 1847, col. 364 - 370 ( online at the Biodiversity Heritage Library ).
  • Sulla fibra muscolare . In: Il Tempo, Giornale di Medicina, Chirurgia e Scienze affini. tape II , 1858, p. 328-338 .


Web links

Commons : Giovanni Battista Amici  - Collection of Images

Individual evidence

  1. a b c d e f g h i j k l m n o p q Prof. Dr. Paolo Buffa, Modena: Giovan Battista Amici . In: Hugo Freund and Alexander Berg (eds.): History of microscopy. Life and work of great explorers. Volume III. Applied science and technology. Umschau Verlag, Frankfurt am Main 1966, p. 1-14 .
  2. a b c d e f g h i j Hugo von Mohl: Giambattista Amici . In: Hugo von Mohl, DFL von Schlechtendal (Hrsg.): Botanische Zeitung . tape 21 . Leipzig 1863. Online link
  3. ^ “Biographical note” on the Giovanni Battista Amici website of the Scuola Normale Superiore di Pisa. Retrieved January 1, 2017
  4. ^ Meyers Konversations-Lexikon . An encyclopedia of common knowledge. Vol. 1, 3rd edition, Verlag des Bibliographisches Institut, Leipzig 1874. Pages 485–486. online version .
  5. Wolfgang Schreier: History of Physics. An outline , Berlin 1988 (VEB Deutscher Verlag der Wissenschaften), p. 309.
  6. ^ Giovanni Battista Amici on the Florida State University's Molecular Expressions website. Retrieved January 1, 2017
  7. ^ Giovanni Battista Amici on the Encyclopædia Britannica website. Retrieved January 1, 2017
  8. ^ Members of the previous academies. Giovanni Battista Amici. Berlin-Brandenburg Academy of Sciences , accessed on February 15, 2015 .
  9. ^ Website 3809 Amici (1984 FA) of the Jet Propulsion Laboratory at the California Institute of Technology
  10. Amicit on . Original work: Neues Jahrbuch für Mineralogie, Monatshefte (1979), 481. The English Wikipedia has an article on Amicite .
  11. "Papers, reports, scientific letters" on the Giovanni Battista Amici website of the Scuola Normale Superiore di Pisa. Retrieved January 8, 2017