History of science

• Daniel Le Clerc publishes Histoire de la médecine in Geneva
  Geneva
  Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...
  
  , the first comprehensive work on the subject.

Mathematics

• Guillaume de l'Hôpital
  Guillaume de l'Hôpital
  Guillaume François Antoine, Marquis de l'Hôpital was a French mathematician. His name is firmly associated with l'Hôpital's rule for calculating limits involving indeterminate forms 0/0 and ∞/∞...
  
   publishes Analyse des Infiniment Petits pour l'Intelligence des Lignes Courbes, the first textbook on differential calculus
  Differential calculus
  In mathematics, differential calculus is a subfield of calculus concerned with the study of the rates at which quantities change. It is one of the two traditional divisions of calculus, the other being integral calculus....
  
  , including a statement of his rule
  L'Hôpital's rule
  In calculus, l'Hôpital's rule uses derivatives to help evaluate limits involving indeterminate forms. Application of the rule often converts an indeterminate form to a determinate form, allowing easy evaluation of the limit...
  
   for the computation of certain limit
  Limit (mathematics)
  In mathematics, the concept of a "limit" is used to describe the value that a function or sequence "approaches" as the input or index approaches some value. The concept of limit allows mathematicians to define a new point from a Cauchy sequence of previously defined points within a complete metric...
  
  s.
• Jakob Bernoulli and Johann Bernoulli
  Johann Bernoulli
  Johann Bernoulli was a Swiss mathematician and was one of the many prominent mathematicians in the Bernoulli family...
  
   solve the brachistochrone curve
  Brachistochrone curve
  A Brachistochrone curve , or curve of fastest descent, is the curve between two points that is covered in the least time by a point-like body that starts at the first point with zero speed and is constrained to move along the curve to the second point, under the action of constant gravity and...
  
   problem, the first result in the calculus of variations
  Calculus of variations
  Calculus of variations is a field of mathematics that deals with extremizing functionals, as opposed to ordinary calculus which deals with functions. A functional is usually a mapping from a set of functions to the real numbers. Functionals are often formed as definite integrals involving unknown...
  
  .

Deaths

• April 30 - Robert Plot
  Robert Plot
  Robert Plot was an English naturalist, first Professor of Chemistry at the University of Oxford, and the first keeper of the Ashmolean Museum....
  
  , English
  English people
  The English are a nation and ethnic group native to England, who speak English. The English identity is of early mediaeval origin, when they were known in Old English as the Anglecynn. England is now a country of the United Kingdom, and the majority of English people in England are British Citizens...
  
   naturalist
  Naturalist
  Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
  
   and chemist
  Chemist
  A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...
  
   (b. 1640
  1640 in science
  The year 1640 in science and technology involved some significant events.-Botany:* John Parkinson publishes Theatrum Botanicum:The Theater of Plants, or, An Herbal of a Large Extent.-Exploration:...
  
  )
• Jean Richer
  Jean Richer
  Jean Richer was a French astronomer and assistant of Giovanni Domenico Cassini.Between 1671 and 1673 he traveled to Cayenne at the request of the French Academy of Sciences to observe Mars during its perigee...
  
  , French
  French people
  The French are a nation that share a common French culture and speak the French language as a mother tongue. Historically, the French population are descended from peoples of Celtic, Latin and Germanic origin, and are today a mixture of several ethnic groups...
  
   astronomer
  Astronomer
  An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
  
   (b. 1630
  1630 in science
  The year 1630 in science and technology involved some significant events.-Technology:* Cornelius Drebbel produces an early form of magic lantern or slide projector.-Births:* September 13 - Olof Rudbeck, Swedish physiologist...
  
  )