Nicolas Steno : biography

Steno’s work on shark teeth led him to the question of how any solid object could come to be found inside another solid object, such as a rock or a layer of rock. The "solid bodies within solids" that attracted Steno’s interest included not only fossils, as we would define them today, but minerals, crystals, encrustations, veins, and even entire rock layers or strata. He published his geologic studies in De solido intra solidum naturaliter contento dissertationis prodromus, or Preliminary discourse to a dissertation on a solid body naturally contained within a solid in 1669. This book was his last scientific work of note. Steno was not the first to identify fossils as being from living organisms; his contemporaries Robert Hooke and John Ray also argued that fossils were the remains of once-living organisms.

Geology and stratigraphy

Steno, in his Dissertationis prodromus of 1669 is credited with three of the defining principles of the science of stratigraphy: the law of superposition: "… at the time when any given stratum was being formed, all the matter resting upon it was fluid, and, therefore, at the time when the lower stratum was being formed, none of the upper strata existed"; the principle of original horizontality: "Strata either perpendicular to the horizon or inclined to the horizon were at one time parallel to the horizon"; the principle of lateral continuity: "Material forming any stratum were continuous over the surface of the Earth unless some other solid bodies stood in the way"; and the principle of cross-cutting relationships: "If a body or discontinuity cuts across a stratum, it must have formed after that stratum." These principles were applied and extended in 1772 by Jean-Baptiste L. Romé de l’Isle. Steno’s ideas still form the basis of stratigraphy and were key in the development of James Hutton’s theory of infinitely repeating cycles of seabed deposition, uplifting, erosion, and submersion.

Steno’s landmark theory that the fossil record was a chronology of different living creatures in different eras was a sine qua non for Darwin’s theory of natural selection.

Crystallography

Steno gave the first accurate observations on a type of crystal in his 1669 book "De solido intra solidum naturaliter contento". The principle in crystallography, known simply as Steno’s law, or Steno’s law of constant angles, states that the angles between corresponding faces on crystals are the same for all specimens of the same mineral. Steno’s seminal work paved the way for the law of the rationality of the crystallographic indices of French mineralogist René-Just Haüy in 1801. This fundamental breakthrough formed the basis of all subsequent inquiries into crystal structure.

Legacy

Steno’s life and work has been studied, in particular in relation to the developments in geology in the late nineteenth century.

• The Steno Museum in Aarhus, Denmark, named after Nicolas Steno, holds exhibitions on the history of science and medicine. It also operates a planetarium and a medicinal herb garden.
• Impact craters on Mars () and the Moon are named in his honor.
• The mineral stenonite was named in his honour., Retrieved on 26 November 2012.
• The Catholic parish church of Grevesmühlen, North Germany, built from 1989 to 1991, is dedicated to Nicolas Steno.
• In 1950 the "Niels Steensens Gymnasium", a Catholic preparatory school, was founded by the Jesuit Order in Copenhagen.
• Steno Diabetes Center, a research and teaching hospital dedicated to diabetes in Gentofte, Denmark, was named after Nicolas Steno.
• The Istituto Niels Stensen was founded in 1964 in Florence, Italy. Administered by the Jesuit Order, it is dedicated to his memory.
• On 11 January 2012, Steno was commemorated with a Google doodle.

Early life and career

Nicolas Steno ( Latinized to Nicolaus Stenonis or Nicolaus Stenonius) was born in Copenhagen on New Year’s Day 1638 (Julian calendar), the son of a Lutheran goldsmith who worked regularly for King Christian IV of Denmark. Suffering from an unknown disease, he grew up in isolation during his childhood. In 1644 his father died, after which his mother married another goldsmith. In 1654–1655, 240 pupils of his school died because of the plague. Across the street lived Peder Schumacher (who would offer Steno a post as professor in Copenhagen in 1671). At the age of 19, Steno entered the University of Copenhagen to pursue medical studies. After completing his university education, Steno set out to travel through Europe; in fact, he would be on the move for the rest of his life. In the Netherlands, France, Italy and Germany he came into contact with prominent physicians and scientists. These influences led him to use his own powers of observation to make important scientific discoveries. At a time when scientific questions were mostly answered by appeal to ancient authorities, Steno was bold enough to trust his own eyes, even when his observations differed from traditional doctrines.

At the urging of Thomas Bartholin, Steno first travelled to Rostock, then to Amsterdam, where he studied anatomy under and lodged at Gerard Blasius, focusing on the Lymphatic system. Within a few months Steno moved to Leiden, where he met the students Jan Swammerdam, Frederik Ruysch, Reinier de Graaf, Franciscus de le Boe Sylvius, a famous professor, and Baruch Spinoza.. See At the time Descartes was publishing on the working of the brain, and Steno did not think his explanation of the origin of tears produced by the brain was correct. He travelled to Paris where he was invited by Henri Louis Habert de Montmor and Pierre Bourdelot, and met Ole Borch and Melchisédech Thévenot who were all interested in new research and demonstrations of his skills. In 1665 Stensen travelled to Saumur, Bordeaux and Montpellier, where he met Martin Lister and William Croone, who introduced Steno’s work to the Royal Society.

After travelling through France, he settled in Italy in 1666. At first as professor of anatomy at the University of Padua and then in Florence as in-house physician of Grand Duke of Tuscany Ferdinando II de’ Medici, who supported arts and science and whom Steno had met in Pisa. Steno was invited to live in the Palazzo Vecchio, in return he had to gather a Cabinet of curiosities. Steno went to Rome and met Pope Alexander VII and Marcello Malpighi, who he admired. On his way back he watched a Corpu Christi procession in Livorno and wondered if he had the right belief.Kooijmans, L. (2007) Gevaarlijke kennis, p. 99-100. In Florence Steno focused on the muscular system and the nature of muscle contraction. He became a member of Accademia del Cimento and had long discussions with Francesco Redi. Like Vincenzio Viviani, Steno proposed a geometrical model of muscles to show that a contracting muscle changes its shape but not its volume.

Major works

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