Baruch Spinoza

SpinozaBenedict de SpinozaBenedict Spinoza
One of the people he knew was Niels Stensen, a brilliant Danish student in Leiden; others included Albert Burgh, with whom Spinoza is known to have corresponded. Benedito de Espinoza was born on 24 November 1632 in the Jodenbuurt in Amsterdam, Netherlands. He was the second son of Miguel de Espinoza, a successful, although not wealthy, Portuguese Sephardic Jewish merchant in Amsterdam. His mother, Ana Débora, Miguel's second wife, died when Baruch was only six years old. Spinoza's mother tongue was Portuguese, although he also knew Hebrew, Spanish, Dutch, perhaps French, and later Latin. Although he wrote in Latin, Spinoza learned the language only late in his youth.

René Descartes

DescartesCartesianRene Descartes
The next year, under the name "Poitevin", he enrolled at the Leiden University to study mathematics with Jacobus Golius, who confronted him with Pappus's hexagon theorem, and astronomy with Martin Hortensius. In October 1630 he had a falling-out with Beeckman, whom he accused of plagiarizing some of his ideas. In Amsterdam, he had a relationship with a servant girl, Helena Jans van der Strom, with whom he had a daughter, Francine, who was born in 1635 in Deventer. She died of scarlet fever at the age of 5. Unlike many moralists of the time, Descartes did not deprecate the passions but rather defended them; he wept upon Francine's death in 1640.

Geologic time scale

geologic timescalegeologic timeperiod
A major shift in thinking came when James Hutton presented his Theory of the Earth; or, an Investigation of the Laws Observable in the Composition, Dissolution, and Restoration of Land Upon the Globe before the Royal Society of Edinburgh in March and April 1785. John McPhee asserts that "as things appear from the perspective of the 20th century, James Hutton in those readings became the founder of modern geology". Hutton proposed that the interior of Earth was hot, and that this heat was the engine which drove the creation of new rock: land was eroded by air and water and deposited as layers in the sea; heat then consolidated the sediment into stone, and uplifted it into new lands.

Deep time

geological timegeologically recentdeep past
As mathematician John Playfair, one of Hutton's friends and colleagues in the Scottish Enlightenment, remarked upon seeing the strata of the angular unconformity at Siccar Point with Hutton and James Hall in June 1788, "the mind seemed to grow giddy by looking so far into the abyss of time". Early geologists such as Nicolas Steno (1638-1686) and Horace-Bénédict de Saussure (1740-1799) had developed ideas of geological strata forming from water through chemical processes, which Abraham Gottlob Werner (1749–1817) developed into a theory known as Neptunism, envisaging the slow crystallisation of minerals in the ancient oceans of the Earth to form rock.

Jan Swammerdam

SwammerdamSwammerdam, Jan
Despite his father's wish that he should study theology Swammerdam started to study medicine in 1661 at the University of Leiden. He studied under the guidance of Johannes van Horne and Franciscus Sylvius. Among his fellow students were Frederik Ruysch, Reinier de Graaf and Niels Stensen. While studying medicine Swammerdam started his own collection of insects. In 1663 Swammerdam moved to France to continue his studies. He studied one year at the Protestant University of Saumur, under the guidance of Tanaquil Faber.

Franciscus Sylvius

Francois de la Boe SylviusFranciscus de le Boe SylviusFranciscus Sylvius de Bouve
In 1658 he was appointed the professor of medicine at the University of Leiden and was paid 1800 guilders which was twice the usual salary. He was the University's Vice-Chancellor in 1669-70. In 1669 Sylvius founded the first academic chemical laboratory. For this reason, the building in which the Institute of Biology of Leiden University is housed has the name Sylvius Laboratory. His most famous students were Jan Swammerdam, Reinier de Graaf, Niels Stensen and Burchard de Volder. He founded the Iatrochemical School of Medicine, according to which all life and disease processes are based on chemical actions.


DutchThe NetherlandsHolland
All of Descartes' major work was done in the Netherlands since he studied at Leiden University — as did throughout the centuries geologist James Hutton, British Prime Minister John Stuart, U.S. President John Quincy Adams, Physics Nobel Prize laureate Hendrik Lorentz and Islam critic Ayaan Hirsi Ali. The Dutch scientist Christiaan Huygens (1629–1695) discovered Saturn's moon Titan, argued that light travelled as waves, invented the pendulum clock and was the first physicist to use mathematical formulae. Antonie van Leeuwenhoek was the first to observe and describe single-celled organisms with a microscope.

Cross-cutting relationships

principle of cross-cutting relationshipscross-cutscross-cutting
Hutton, James. Theory of the Earth, 1795. Lyell, Charles. Principles of Geology, 1830.

Frederik Ruysch

Frederick RuyschFredericus RuyschRuysch
Fascinated by anatomy, he studied at the university of Leiden, under Franciscus Sylvius. His fellow students were Jan Swammerdam, Reinier de Graaf and Niels Stensen. The dissection of corpses was relatively expensive and cadavers were scarce, which lead Ruysch to find alternative ways to prepare the organs. In 1661, he married Maria Post, daughter of the Dutch architect, Pieter Post. He graduated in 1664 with a thesis on pleuritis. Ruysch became praelector of the Amsterdam surgeon's guild in 1667. In 1668 he was made the chief instructor to the city's midwives. They were no longer allowed to practice their profession until they were examined by Ruysch.

Age of the Earth

formation of the EarthEarthage of Earth
Nicolas Steno in the 17th century was one of the first naturalists to appreciate the connection between fossil remains and strata. His observations led him to formulate important stratigraphic concepts (i.e., the "law of superposition" and the "principle of original horizontality"). In the 1790s, William Smith hypothesized that if two layers of rock at widely differing locations contained similar fossils, then it was very plausible that the layers were the same age. William Smith's nephew and student, John Phillips, later calculated by such means that Earth was about 96 million years old.

Nicolaes Witsen

Nicolaas WitsenNicolaus Witsen
He studied law at Leiden University, but became more interested in languages and maps. In the 1666–1667 Witsen travelled to Rome and met with Cosimo III de' Medici in Pisa. In Paris he met the scientist Melchisédech Thévenot. In 1668 he travelled to Oxford. In 1674 he married Catherina Hochepied. Four children were born, not surviving childhood. Witsen wrote "Aeloude and hedendaegsche Scheepsbouw en Bestier" in 1671, which quickly became seen as the standard work on the subject. Even an anatomist like Steno read the book. The technique Witsen describes is shell-first, and not frame-first.


Nicolas Steno (1638–1686) is credited with the law of superposition, the principle of original horizontality, and the principle of lateral continuity: three defining principles of stratigraphy. The word geology was first used by Ulisse Aldrovandi in 1603, then by Jean-André Deluc in 1778 and introduced as a fixed term by Horace-Bénédict de Saussure in 1779. On the controversy regarding whether Deluc or Saussure deserves priority in the use the term "geology": William Smith (1769–1839) drew some of the first geological maps and began the process of ordering rock strata (layers) by examining the fossils contained in them. James Hutton (1726-1797) is often viewed as the first modern geologist.

William Charles Wells

WellsWilliam Charles Wells, MDWilliam Wells
Wells then moved to Leiden in the Netherlands and matriculated at the University of Leiden Feb. 19, 1780. On this University he prepared his dissertation. This was the Inaugural Thesis, published at Edinburgh in 1780 when he took the degree of Doctor of Medicine; the subject of his thesis was Cold (De frigore). The title description of his thesis is: Disputatio medica, inauguralis, de frigore ... - Edinburgi : Balfour et Smellie, 1780. Early in 1781 he returned to Carolina to put his family's affairs in order.


classicistclassical scholarclassical
Classics or classical studies is the study of classical antiquity. It encompasses the study of the Greco-Roman world, particularly of its languages and literature (Ancient Greek and Classical Latin) but also of Greco-Roman philosophy, history, and archaeology. Traditionally in the West, the study of the Greek and Roman classics is considered one of the cornerstones of the humanities and a fundamental element of a rounded education. The study of classics has therefore traditionally been a cornerstone of a typical elite education.


Anatomy (Greek anatomē, "dissection") is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated over immediate (embryology) and long (evolution) timescales.


EgyptianEGYArab Republic of Egypt
Egypt, officially the Arab Republic of Egypt, is a country in the northeast corner of Africa, whose territory in the Sinai Peninsula extends beyond the continental boundary with Asia, as traditionally defined. Egypt is bordered by the Gaza Strip (Palestinian territories) and Israel to the northeast, the Gulf of Aqaba and the Red Sea to the east, Sudan to the south, Libya to the west, and the Mediterranean Sea to the north. Across the Gulf of Aqaba lies Jordan, across the Red Sea lies Saudi Arabia, and across the Mediterranean Sea lie Greece, Cyprus and Turkey, although none of these share a land border with Egypt.

Internet Archive

Archive.orgWayback Machinearchived
The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge." It provides free public access to collections of digitized materials, including websites, software applications/games, music, movies/videos, moving images, and millions of public-domain books. In addition to its archiving function, the Archive is an activist organization, advocating for a free and open Internet.

Linda Hall Library

Linda Hall Library of Science Library
The Linda Hall Library is a privately endowed American library of science, engineering and technology located in Kansas City, Missouri, sitting "majestically on a 14 acre urban arboretum." It is the "largest independently funded public library of science, engineering and technology in North America" and "among the largest science libraries in the world."


The idea of overlapping strata tracing back to successive periods was borrowed from the new geological and paleontological work of scholars like William Smith, James Hutton and Charles Lyell. The application of stratigraphy to archaeology first took place with the excavations of prehistorical and Bronze Age sites. In the third and fourth decades of the 19th-century, archaeologists like Jacques Boucher de Perthes and Christian Jürgensen Thomsen began to put the artifacts they had found in chronological order.


Nicholas Steno first observed the law of constancy of interfacial angles (also known as the first law of crystallography) in quartz crystals in 1669. This was later generalized and established experimentally by Jean-Baptiste L. Romé de l'Islee in 1783. René Just Haüy, the "father of modern crystallography", showed that crystals are periodic and established that the orientations of crystal faces can be expressed in terms of rational numbers, as later encoded in the Miller indices. In 1814, Jöns Jacob Berzelius introduced a classification of minerals based on their chemistry rather than their crystal structure.

Anna Maria van Schurman

Anna van SchurmanAnna Maria SchurmanSchurman, Anna Maria van
It was published 1648 by Friedrich Spanheim, professor of theology at Leiden University through the Leiden-based publisher Elzeviers. Schurman's The Learned Maid or, Whether a Maid may be a Scholar had grown out of her correspondence on women's education with theologians and scholars across Europe. In it she advances Jane Grey as an example of the value of female education. Schurman argued that educating women in languages and the Bible will increase their love of God. While an increasing number of royal and wealthy families chose to educate their daughters, girls and women did not have formal access to education. Schurman argued that "A Maid may be a Scholar...

Flood geology

vapor canopyBiblical flooddiluvialism
In 1616 Nicolas Steno showed how chemical processes changed organic remains into stone fossils. His fundamental principles of stratigraphy published in 1669 established that rock strata formed horizontally and were later broken and tilted, though he assumed these processes would occur within 6,000 years including a worldwide Flood. In his influential Principles of Philosophy of 1644, René Descartes applied his mechanical physical laws to envisage swirling particles forming the Earth as a layered sphere.

Timeline of geology

This book acts as the standard mining and assaying text for the next 250 years. 1596 – Abraham Ortelius, Flemish-Spanish cartographer, first envisages the continental drift theory. 1603 – Ulisse Aldrovandi coins the term Geology. 1669 – Nicolas Steno puts forward his theory that sedimentary strata had been deposited in former seas, and that fossils were organic in origin. 1701 – Edmond Halley suggests using the salinity and evaporation of the Mediterranean to determine the age of the Earth. 1743 – Dr Christopher Packe produces a geological map of south-east England. 1746 – Jean-Étienne Guettard presents the first mineralogical map of France to the French Academy of Sciences. 1760 – John Michell

Sir John Clerk, 2nd Baronet

Sir John Clerk of PenicuikSir John ClerkJohn Clerk of Penicuik
He was the father of George Clerk Maxwell and John Clerk of Eldin, both of them friends of James Hutton and the great-great-grandfather of the famous physicist James Clerk Maxwell. John Clerk was son of Sir John Clerk, 1st Baronet by his first wife Elizabeth, daughter of Henry Henderson of Elvington. He had a legal education first at University of Glasgow and then at Leiden University. During 1697 and 1698 he went on a Grand Tour and in 1700 was admitted to the Scottish Bar. He was a member of the Parliament of Scotland for Whithorn from 1702 to 1707, and a Commissioner for the Union of Parliaments for the Whig Party: he sat in the first Parliament of Great Britain in 1707.

Historical geology

geological historyPaleogeologistpaleogeology
Nicolaus Steno, also known as Niels Stensen, was the first to observe and propose some of the basic concepts of historical geology, called the "father of geology". One of these concepts was that fossils originally came from living organisms. The other, more famous, observations are often grouped together to form the laws of stratigraphy. James Hutton and Charles Lyell also contributed to early understanding of the Earth's history with their observations at Edinburgh in Scotland concerning angular unconformity in a rock face and it was in fact Lyell that influenced Charles Darwin greatly in his theory of evolution by speculating that the present is the key to the past.