Sir Isaac Newton (1642-1726) 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. His monograph Philosophiae Naturalis Principia Mathematica, published in 1687, laid the foundations for most of classical mechanics. In this work, Newton described universal gravitation and the three laws of motion, which dominated the scientific view of the physical universe for the next three centuries. Newton showed that the motion of objects on Earth and that of...

"Great Astronomers" from Robert Stawell Ball. Irish astronomer who founded the screw theory (1841-1913).

"Time and Tide" from Robert Stawell Ball. Irish astronomer who founded the screw theory (1841-1913).

Sir Robert Stawell Ball FRS (1 July 1840 - 25 November 1913) was an Irish astronomerwho founded the screw theory He was the son of naturalist Robert Ball 2] and Amelia Gresley Hellicar. He was born in Dublin. Ball worked for Lord Rosse from 1865 to 1867. In 1867 he became Professor of Applied Mathematics at the Royal College of Science in Dublin. There he lectured on mechanics and published an elementary account of the science. In 1874 Ball was appointed Royal Astronomer of Ireland and Andrews Professor of Astronomy in the University of Dublin at Dunsink Observatory. Ball contributed to the...