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Carlo Antonio Tortoni, screw-barrel compound microscope 1683

Carlo Antonio Tortoni (1640-1700) was a Jesuit priest, physicist, and mathematician born in Recanati, near Ancona, in the Papal Marches. After being appointed chamberlain at the court of Pope Alexander VII, he moved to Rome, where he lived during the last decades of the seventeenth century. Aside from his interest in the sciences and the development of scientific instruments of his time, little else is known about him. In Rome, Tortoni joined the Physico-Mathematical Academy (Accademia Fisico-Matematica), which was established in 1677 under the patronage of Queen Christina of Sweden (1626-1689).

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Tortoni is primarily known for designing this portable handheld screw-barrel microscope in 1683, which he demonstrated in the palace of Giovanni Ciampini (1633-1698) on August 5, 1685. The screw served three key purposes: it facilitated focus adjustment for observed objects, allowed for a range of magnifications by changing the focal length, and enabled the instrument to function as a telescope. Tortoni provided a partial description of his microscope in a publication but omitted the technical details due to concerns about plagiarism. Consequently, he shared only certain aspects of the instrument rather than the complete design, which can be observed by comparing the figures with the entire apparatus.  Due to poor health, he was unable to document his microscopes as he wished and was reluctant to reveal his studies until they were fully developed, first on paper and then in practice.

In 1687, he introduced a new design for a smaller screw-barrel microscope that featured a five-lens system, including a doublet of plano-convex lenses. His fellow members praised this invention, noting that the microscope's compact tube, which measured just 2 inches in length, represented a significant innovation in terms of manageability and convenience. It allowed for observations of objects at high magnification and enabled examination even in low-light conditions, unlike other microscopes of the time. The discussions centered around the microscope's composition and features during the meeting. Compared to similar instruments, it was unanimously concluded that Tortoni’s design was novel and original. Notably, the mechanism that connected the five parts of the instrument was also unique.

Quickly, his fellow countrymen began to replicate the "screw-barrel" principle in their microscope designs, adding innovative features. Notably, Filippo Bonanni (or Buonanni, 1638-1725) introduced a spring mechanism that pushed the slider toward the frame holding the object to be observed, ensuring it aligned with the fixed ocular lens. It wasn't until the early twentieth century that Tortoni was officially recognized as the true inventor of this principle.

Portrait of Carlo Antonio Tortoni, from Istruzione delle due sorti di microscopii tortoniani nuovamente inventati (Rome: 1687) by Carlo Antonio Tortoni. Houghton Library, Harvard University, public domain.

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The value attributed to Tortoni for his innovative techniques is evident in his expertise and meticulous approach to describing his observations through microscopy. He remarked on the shapes and movements of the new creatures he studied, stating: "...in cases of gangrene, the majority of those observed could be a mine of worms, as well as in sores that contained varying quantities of animals in different colors, some with black heads. In human blood, one can see continuous changes resembling brilliant little diamonds, some in conical shapes, while others look like small seeds of changing garnets. In febrile blood, pieces of vermilion watermelon can still be recognized, along with areas of ash color that contain small, worm-like creatures of citron color. In cases of malignant fevers, the blood is filled with black points, which knowledgeable doctors say nature transmits to the surface of the skin, commonly referred to as petechiae."

In addition to inventing the screw-barrel microscope, Tortoni should also be remembered for his pioneering use of microscopy in medical experimentation. The versatility of this Italian scientist is evident in another of his publications, which addresses a topic seemingly far removed from his beloved microscopes: the creation of a therapeutic balm. Tortoni ventured into this new field, captivated by the tiny world he observed through his instruments. In this world, minute creatures and other unidentified entities exhibit various behaviors depending on their environments.

Impressed by his microscopic observations, Tortoni recognized the need for new remedies to address what he believed were the causes of many diseases. As a result, he developed a balm known as Balsamo Tortoriano, which he claimed could miraculously cure numerous ailments. He detailed his findings in a publication dated 1689. However, the exact composition of the balm remains unknown, as Tortoni closely guarded it out of mistrust and fear of plagiarism. Furthermore, the effectiveness of this medicine is still unverified. Utilizing his microscope, Tortoni conducted experiments on insects and other forms of life he identified and observed in his environment, testing the effectiveness of his medicine.

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To the best of our knowledge, only two examples of this microscope have survived. One, designated No. 238, is part of the Kern Collection of historical scientific instruments. It is made of boxwood but does not have a case. The other example, which is included in my collection, is constructed from ivory and comes in a fitted wooden case. This case features inner chamois lining and compartments for two ivory sliders, along with special brass tweezers for handling them. Additionally, the outer cover is coated with hide and is hot-stamped with motifs of the Florentine (Medici) fleur-de-lys. It also has an iron-hinged top equipped with a lock.

This suggests that this microscope was part of the collection of scientific instruments held by Cosimo III de' Medici (1642 – 1723), Grand Duke of Tuscany from 1670 until his death in 1723.

Medici Grand Dukes as Patrons of Science

The extensive correspondence found in the Medici Grand Ducal archives, dating from 1537 to 1743, highlight the Medici family's significant interest in various fields of natural and applied sciences. These fields included hydraulics, engineering, botany, human and veterinary anatomy, pharmacology, metallurgy, mineralogy, cartography, meteorology, astrology, astronomy, mathematics, optics, and alchemy.
The Medici's patronage of scientific studies, scientists, and technological advancements was rooted in a fundamental belief: that knowledge of science and mastery of technology would enhance their political power. They were interested in how scientific discoveries and applications could improve everyday life, commerce, and communication.
The Medici supported significant figures such as Luca Ghini in botany, Andreas Vesalius in anatomy, Galileo Galilei in astronomy and mathematics, Nicolas Steno in anatomy and geology, and Francesco Redi in medicine. They contributed to various educational institutions, teaching hospitals like Santa Maria Nuova in Florence, academies such as the Accademia del Cimento in Florence, and botanical gardens like the Orto Botanico in Pisa and the Giardino dei Semplici in Florence. They also played a role in the publication of both ancient and modern scientific works.
Cosimo I had a particular interest in acquiring the secrets of glassmaking, sugar refining, and porcelain production. Ferdinand began assembling a collection of scientific artifacts and instruments, while Cosimo II showed an affinity for nautical engineering.

Over the years, the Medici Family, renowned patrons of art and science, assembled an impressive collection of scientific instruments. It began with Cosimo I, the founder of the Grand Duchy of Tuscany. His sons and successors further enriched it: Francesco I, who focused mainly on natural history and alchemical collections; and Ferdinando I, who acquired numerous mathematical, nautical, and cosmographical instruments. Cosimo II had the distinction of adding Galileo's groundbreaking instruments to the collection. Later, beautifully crafted glass thermometers were produced in the glassworks of Palazzo Pitti for the Accademia del Cimento, which was established by Grand Duke Ferdinando II and Prince Leopoldo de' Medici. A notable figure among the later Medici rulers is Cosimo III, who was a patron of the mathematician Vincenzo Viviani, Galileo's last disciple.

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Cosimo III de' Medici, Grand Duke of Tuscany (public domain)

In 1670, at the age of twenty-eight, Cosimo de' Medici inherited the Grand Dukedom of Tuscany from his father, Ferdinando II de' Medici. He ruled for over fifty years as Cosimo III. Although his personal and political life could hardly be considered successful, his support for the arts and sciences somewhat compensated for his inability to reverse the decline of the state that had begun during his father's reign. During this period, the arts, sciences, and even religion were deeply interconnected, with every educated individual often acting as a sort of pantologist, exploring a wide range of subjects. This integration was partly due to the study of the seven liberal arts, a curriculum established in classical Rome that became the foundation for university education from the 12th century onward. Students would spend six years studying these subjects—grammar, logic, rhetoric, geometry, arithmetic, astronomy, and music—to earn a master’s degree.

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