Astronomy

• Montanari detects the variability
  Variable star
  A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
  
   of the eclipsing binary Algol.

Biology

• Robert Morison
  Robert Morison
  Robert Morison was a Scottish botanist and taxonomist. A forerunner of John Ray, he elucidated and developed the first systematic classification of plants.-Life:...
  
   publishes Praeludia Botanica, emphasising use of the structure of a plant's fruits for its classification.
• Francis Willughby
  Francis Willughby
  thumbnail|200px|right|A page from the Ornithologia, showing [[Jackdaw]], [[Chough]], [[European Magpie|Magpie]] and [[Eurasian Jay|Jay]], all [[Corvidae|crows]]....
  
   and John Ray
  John Ray
  John Ray was an English naturalist, sometimes referred to as the father of English natural history. Until 1670, he wrote his name as John Wray. From then on, he used 'Ray', after "having ascertained that such had been the practice of his family before him".He published important works on botany,...
  
   publish "Experiments concerning the motion of sap in trees, made this spring".
• Jan Swammerdam
  Jan Swammerdam
  Jan Swammerdam was a Dutch biologist and microscopist. His work on insects demonstrated that the various phases during the life of an insect—egg, larva, pupa, and adult—are different forms of the same animal. As part of his anatomical research, he carried out experiments on muscle contraction...
  
   publishes Historia Insectorum Generalis in the Netherlands
  Netherlands
  The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
  
  , explaining the process of metamorphosis
  Metamorphosis
  Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
  
   in insect
  Insect
  Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
  
  s.

Geology

• Nicolas Steno
  Nicolas Steno
  Nicolas Steno |Latinized]] to Nicolaus Steno -gen. Nicolai Stenonis-, Italian Niccolo' Stenone) was a Danish pioneer in both anatomy and geology. Already in 1659 he decided not to accept anything simply written in a book, instead resolving to do research himself. He is considered the father of...
  
   puts forward his theory that sedimentary strata had been deposited in former seas, and that fossil
  Fossil
  Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
  
  s are organic in origin.

Mathematics

• October 29 - Isaac Newton
  Isaac Newton
  Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
  
   is appointed Lucasian Professor of Mathematics at the University of Cambridge
  University of Cambridge
  The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
  
  .

Physics

• Rasmus Bartholin
  Rasmus Bartholin
  Rasmus Bartholin was a Danish scientist and physician. As part of his studies, he travelled in Europe for ten years. Professor at the University of Copenhagen, first in Geometry, later in Medicine...
  
   publishes his observation of the birefringence
  Birefringence
  Birefringence, or double refraction, is the decomposition of a ray of light into two rays when it passes through certain anisotropic materials, such as crystals of calcite or boron nitride. The effect was first described by the Danish scientist Rasmus Bartholin in 1669, who saw it in calcite...
  
   of a light ray by Iceland spar
  Iceland spar
  Iceland spar, formerly known as Iceland crystal, is a transparent variety of calcite, or crystallized calcium carbonate, originally brought from Iceland, and used in demonstrating the polarization of light . It occurs in large readily cleavable crystals, easily divisible into rhombs, and is...
  
   (calcite
  Calcite
  Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
  
  ).

Births

• May 26 - Sébastien Vaillant
  Sébastien Vaillant
  Sébastien Vaillant was a French botanist.Vaillant was born at Vigny, Val d'Oise. He studied medicine at Pontoise, and then moved to Paris to practice as a surgeon, where he studied botany at the Jardin des Plantes under Joseph Pitton de Tournefort.Vaillant was appointed to the staff of the Jardin...
  
  , 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...
  
   botanist (d. 1722
  1722 in science
  The year 1722 in science and technology involved some significant events.-Chemistry:* René Antoine Ferchault de Réaumur publishes his work on metallurgy, L'Arte de convertir le fer forge en acier, which describes how to convert iron into steel....
  
  )