Niels Stensen

Niels Stensen (born the January 10th 1638 in Copenhagen - died the November 26th 1686 with Schwerin) is an anatomist and geologist of Danish origin . It was one of the first to formulate principles in geology, a branch then well little known of the natural science. Most known of them is the Law of the superposition according to which the roadbase of a sedimentary succession is increasingly more recent than the subjacent layers, with less of later rehandlings.

Its life is mainly marked by its personal conflict between the religious explanations of the natural phenomena having course then and the scientific discoveries which it made in this field. That led to its disastrous end.

Its life and its discoveries

After having finished its academic works in Copenhagen, Steno travelled to Europe. He would have liked to travel all his life. During its voyages, it came into contact with famous physicists and other scientists, especially in the Netherlands, to France and Italy.

In 1660 it began medicine with Leyde, which passed then for the center of medical knowledge to Europe. In 1665 it left for Florence. By its anatomical studies, it drew the attention of the large-duke of Florence, Ferdinand II of Medici. Ferdinand granted a station at the hospital to him, which left him little time for its own studies. Moreover, he was elected in Accademia del Cimento, a group of researchers inspired by the scientific approaches of Galileo.

Its studies in anatomy related to the muscular system and the way in which the muscular contraction took place. He used the geometry of the muscles to show that a muscle in contraction changed form well, but not of volume.

Research in geology

In October 1666 two fishermen took enormous a Requin close to Leghorn. Shorthand writing studied the head and left a publication it on this subject in 1667. By studying the teeth of the shark he noticed that they had many common points with - what proved to be later - fossilized teeth of sharks found in mountain. At the time one called them glossopetrae or " stones of langue". Pline Old the had explained why these stones came either from the sky or of the moon. Others still claimed that the fossils pushed naturally in the rocks. Shorthand writing, with its extraordinary gift of precise observation, managed from there to explain why the glossopetrae resembled the teeth of shark, because they came from the mouth of sharks died in the past, buried in the mud and the sand which had dried later on. To explain the difference in the composition of the teeth of alive sharks and the stones in language, Steno developed the theory which the fossils could change composition, without that being visible outside. This can be regarded as an early precursor of the theory of the particles: the matter consists of extremely small particles, which are interchangeable.

At the time of the discoveries of Shorthand writing the definition of the word Fossile was different from the current one: all the excavated objects were called fossil, as well the crystals, the ores that the petrified remainders of former life (fossils in the modern direction of the word). Shorthand writing thus noticed that the rocks contained objects which were not formed inside those, but which were included there during their formation. That led to the theory of the processes of Sédimentation, that Steno described in 1669, in the wanted work as introduction Of solido will intra solidum naturaliter contento dissertationis prodromus . Since it attached always more importance to the religion than with science, it remained about it with this introduction and never wrote a complete work on this subject, although that had been its intention.

Principles of Shorthand writing

Shorthand writing formulated three principles (or laws) which proved to be of great importance for the Sédimentologie and the Stratigraphie.

The principle of primary horizontality

On the basis of the assumption that any rock and any mineral being were liquid there, Steno drew some that the layers of rock and the sediments equivalent were formed by the fact that the particles, in water or another liquid, settle at the bottom. This process should give horizontal layers which are followed. The principle of primary horizontality which results from it implies that layers of rocks which are not (more) in horizontal position are the result of later modifications at the time of sedimentation.

The principle of the superposition

Another principle that Steno formulated known as that when a solid object is surrounded by another solid object (for example a fossil by a sediment), the including object takes the shape of the included object. Shorthand writing concludes from it that the fossils and the crystals were to be petrified before the formation of the rock. If a " hone langue" had pushed in a rock, the stone of language was to be itself formed according to the rock, just like a root, which pushes in a crack and fills it.

This was precisely well the case of the veins and crystals developing in the rocks. Shorthand writing drew some that these veins were to be appeared by the fact that liquids percolaient through the rock. According to the idea that including solid matters took their form according to the included matters, Steno came to the principle of the superposition : the most recent layers were to be appeared above the oldest layers. The Law of Shorthand writing is thus the following one: “the layers of rock are formed successively, with oldest in lower part and most recent above, unless later processes did not modify this principle”. It is this theory which gave its world notoriety to Steno and which made that it can be regarded as the founder of stratigraphy.

In order to explain the many exceptions to the principles of primary horizontality and the superposition, Steno used examples such as the Grotte S, with their erosion of part of the subjacent layer and which during crumblings make that great parts of the higher rock are found on a part much older. This was in fact the first description known of a Disconformité or (in historical stratigraphy) hiatus (one period of not-sedimentation, or no sediment is deposited and that it “thus misses” in a rock one temporal period).

He developed as the assumption as the rocks can be raised by underground forces. Now, a very normal geological phenomenon, but, at the time of Shorthand writing, a revolutionary idea. This explained for him how one could find teeth of sharks in high mountain. In the same way molten rocks (magma) can constitute an exception to the law of the superposition by the fact that as a younger rock, it can be formed under, enters or through older rocks.

This law of Shorthand writing speaks about time Relatif, since two horizontal layers of rock one on the other can be formed with a hiatus of million years (some Sédiment S oceanic) or only few hours (deposits of Marée S).

Principle of side continuity

According to the third law of Shorthand writing, the side principle of continuity , the sedimentary layers is followed in theory laterally, which wants to say horizontally. The sedimentary processes, conclude Steno from it, do not stop at the place where the sediments are found. Thus he explained why the same rock is often found in the shape of hills on the two sides of a valley. Enter, in the valley, this sediment was eroded. Now we know that on large scales sedimentation should not always occur in a side way: a sedimentary Bassin is not unlimited, but it is always at present an important principle of geology.

The religion opposed to science

The religious vision of Shorthand writing was strongly influenced by what he discovered on the scientific level. Although it had received an education Lutheran, Steno strongly doubted its religious designs. After theological studies with Florence, it concludes from it that the Roman Catholicism was the true Church, and it became catholic in 1667.

These religious designs started to be opposed more and more to its scientific observations. More particularly, the difference between the history of the creation (which was regarded at the time as the real report/ratio of the birth of the ground) and the formation of the layers of the ground occupied it extremely.

At the time of its study of two cases of largely widespread rocks in the the Apennines, Steno noticed that the deepest layers did not contain fossils, whereas the layers placed higher were rich in fossils. He explained this in “going back” the sub-bases to before and the roadbases according to the Déluge.

By the fact that Steno was withdrawn more and more in the religion, that as bishop it went to work in Germany and in Denmark, and than it moved away from his entourage, it became increasingly unhappy and that led to its death in misery with Schwerin.

Its life and its work are the object of in-depth studies, in particular since the end of the 19th century, moreover, its virtue and its piety was remarkable. In 1987, the pope Jean-Paul II declared it Bienheureux.

Publications

Observationes anatomicae (1662)
De Musculis and Glandulis Observationum Specimen (1664)
Elementorum myologiæ specimen, seu musculi descriptio geometrica: cui accedunt Canis Carchariæ dissectum caput, and dissectus piscis ex Canum generates (1667)
Discours on the anatomy of the brain (1669)
Of solido will intra solidum naturaliter contento dissertationis prodromus (1669)

General information

In the district of Utrecht Kanaleneiland until there was a few years the Collège Niels Stensen. After a counting of the pupils the school closed its doors during the summer 2003.

internal bonds

Channel of Sténon (Medicine)
Principles of Sténon (Geology, Sedimentology, Stratigraphy)

external bonds

Nicholas Shorthand writing on the Web site of University off California, Berkeley Museum off Paleontology
Niels Stensen
article of Frank Sobiech, which made its doctorate on Stensen
Niels Stensen
Textes
On its biography by Jacques Berg

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