1629 – Christian Huygens was born at the Hague on April 14th. Dutch mathematician, astronomer and physicist.
1651 – He published an essay in which he shewed the fallacy in a system of quadratures proposed by Grégoire de Saint-Vincent, who was well versed in the geometry of the Greeks, but had not grasped the essential points in the more modern methods.
1654 – His attention was directed to the improvement of the telescope.
1655-1656 – As a result of his improvements he was able to resolve numerous astronomical questions
1657 – Huygens wrote a small work on the calculus of probabilities founded on the correspondence of Pascal and Fermat.
1665 – His reputation was now so great that Louis XIV offered him a pension if he would live in Paris, which accordingly then became his place of residence.
1668 – He sent to the Royal Society of London, in answer to a problem they had proposed, a memoir in which (simultaneously with Wallis and Wren) he proved by experiment that the momentum in a certain direction before the collision of two bodies is equal to the momentum in that direction after the collision.
1673 – The most important of Huygens’s work was his Horologium Oscillatorium published at Paris.
1675 – Huygens proposed to regulate the motion of watches by the use of the balance spring, in the theory of which he had been perhaps anticipated in a somewhat ambiguous and incomplete statement made by Hooke.
1681 – The increasing intolerance of the Catholics led to his return to Holland, and after the revocation of the edict of Nantes he refused to hold any further communication with France.
1690 – Huygens published his treatise on light in which the undulatory theory was expounded and explained.
1695 – Died on July 8th in Hague.