Background
Giovanni Battista Amici was born on the 25th of March 1786 in Modena, present-day Italy. Amici was the son of Giuseppe Amici, a ministerial official, and Maria Dalloca, a member of a well-to-do family.
Portrait of Giovanni Battista Amici (Modena, 1786-Florence, 1863), Italian engineer, mathematician and physicist
Portrait of Giovanni Battista Amici (Modena, 1786-Florence, 1863), Italian engineer, mathematician and physicist
The accounting book of the laboratory (Libro de’ conti) recorded the sales of around 270 instruments. With its camera lucida Amici portrayed relatives, friends and several guests of his studio both in Modena and in Florence.
Telescope made by Giovanni Battista Amici
Amici microscope, 1841.
Amici microscope, 1841. Microscope made by Giovanni Battista Amici (1786-1868). It has one eyepiece and one high-power object glass.
Giovanni Battista Amici, portrait photograph.
Giovanni Battista Amici, portrait photograph.
Giovanni Battista Amici`s amicable letter to his brother Pietro on family affairs around the easter holiday.
Bologna University from which Amici graduated in 1808.
The Order of Saints Maurice and Lazarus
Order of Saint Joseph
Astronomer biologist mathematician microscopist physicist scientist
Giovanni Battista Amici was born on the 25th of March 1786 in Modena, present-day Italy. Amici was the son of Giuseppe Amici, a ministerial official, and Maria Dalloca, a member of a well-to-do family.
Amici studied first in Modena where he attended, inter alia, lessons of Geometry and Analysis from Paolo Ruffini (1765-1822), mathematician of international renown. In 1808, he graduated Architect and Engineer at the Bologna University.
After the graduation as an engineer-architect from the University of Bologna in 1807, Amici immediately became a mathematics teacher at the Modena liceo. In 1831 Amici was invited to Florence by the grand duke of Tuscany to head the astronomical observatory and the Royal Museum of Physics and Natural History. He held this office until 1859, when, because of his advanced age of seventy-three, he accepted the less demanding office of director of microscopic research at the museum.
In the early nineteenth century, compound microscopes were much less accurate than the simple microscopes, not only because their objectives caused strong aberrations, especially chromatic ones, but above all because the numerical aperture was not yet known to be the determining factor of the resolving power; therefore construction was governed by the erroneous conviction that enlargement was the most important factor. In 1791 the first achromatic lens for compound microscopes was built as the result of the work of an Amsterdam amateur, F. Beeldsnijder; the images were quite good, but the resolution was only 0.01 mm., while the resolution of simple microscopes reached 0.0015 mm. Only around 1806 did microscopes with achromatic objectives appear on the market, through the efforts of Harmanus Van Deyl, also of Amsterdam; these were instruments that could magnify 150 times and could resolve to 0.005 mm.
This lead was immediately followed by scientists all over the world, especially Chevalier and Nachet, Oberhaiiser and Plossl, Tulley, Pritchard, and Ross, and Amici, who was just embarking on his career. Within thirty years, the efforts of these and many other scientists succeeded in making the resolving power of the compound microscope equal to that of the simple microscope. For example, as early as 1818 Amici, after having built a type of catadioptric microscope that was free of chromatic aberrations, succeeded in appreciably improving the knowledge of the circulation of protoplasm in Chara cells, thereby becoming immediately famous not only as an optician but also as a microscopic biologist.
His most sensational innovation was achieved in 1837 when Amici arrived at a resolving power of 0.001 mm. with a new type of microscope that had a numerical aperture of 0.4 and was capable of magnifying up to 6,000 times. This device consisted of a hemispheric frontal lens applied to the objective; only through this contrivance was it possible to increase the numerical aperture to an appreciable extent. It was the hemispheric lens that permitted maximum use of the compound microscope. All opticians, with the exception of the French, immediately adopted this new design.
The improvement introduced by Amici also led to a significant theoretical clarification. The moderate influence of the magnification in the operation of the microscope was soon recognized and values ranging around 1,000X were generally achieved. It was emphasized, however, that resolution was due mainly to the numerical aperture and to the optical correction by the objective. Amici clearly stated his discovery in a letter of 25 October 1855 to his friend Ottaviano Mossotti, professor at the University of Pisa and a famous optical mathematician.
Amici was so convinced that the numerical aperture was the theoretical factor determining a microscope’s power that he continued to do everything possible to increase it, not only by manufacturing objectives with ever greater numerical aperture (Harting states that in 1856 he purchased from Amici a microscope objective with a numerical aperture of 0.985) but also by inventing the technique of immersion microscopy; he first used water, then olive oil, and finally sassafras oil. He even became aware of the influence that the thickness of the cover glass has on the quality of the image in the microscope.
Amici moved to Florence, where he devoted his attention to other optical processes, although his interest in microscopy never flagged. He invented widely used prisms that still bear his name, and reconsidered the direct-vision prism, which had been forgotten. He also built concave mirrors and astronomical lenses.
While Amici kept increasing the power of his instruments, through his theoretical know-how and his skill in optical processing, he also used them in astronomical and microscopical observations. His findings in microscopy attracted the attention of the entire biological world of his time.
The discovery that made him famous, however, was that of the fertilization of phanerogams, particularly the travel of the pollen tube through the pistil of the flower (1821). His early observations were followed by a heated controversy with the best-known botanists of the world, who for thirty years disputed Amici’s ideas. However, by making ever liner microscopic observations, he finally won over his rivals.
In 1855, when he was 69, he did his third and last trip to Paris on the occasion of the Exposition Universelle. There, his lenses, «modified in order that the plane of half of sphere could be immersed in water or in poppy seed oil, achieved a great success».
At the end of 1859, he was relieved from his role of Director of Astronomic Observatory of Royal Physics and Natural History Museum. Because of his age, this task became too heavy for him and he was titled honorary astronomy professor and person in charge of microscopic observations by the Royal Physics and Natural History Museum of Florence. His last invention, the direct vision prism to be used by the observations of stellar spectra, was done between 1857 and 1860. In 1861, he was President of the Jury Commission for IX Class, Precision Mechanics, and Physics, by the Italian Exposition held in Florence. Thanks to his works and the creation of optic instruments appreciated and imitated worldwide (in that period these were the unique exported high technology instruments from Italy) he showed how the work of scientist and instrument builder should work in synergy spurring them each other. In the same time, he gave birth to the modern tradition of Florentine optic, which thanks to the work of Giovanni Battista Donati, a collaborator of him by the Observatory (the Specola) of Royal Museum, will take to the creation of Galileo workshop in 1870.
On the 10th of April 1863, Giovanni Battista Amici died in Florence.
In his religious affiliation Amici was a Roman Catholic.
Amici was a diligent and skillful observer.
In 1806 he married Teresa Tamanini. They had three children: Vincenzo (born in 1807), Elena (born in 1808), and Valentino (born in 1810).