ABSTRACT
Between 1800 and 1899 the content of science changed profoundly. In physics at the start of the century the Newtonian orthodoxy, of rectilinear forces acting in aetherless space through which light particles travelled, on the whole pre vailed. By 1899 the work of the Dutch physicist Hendrik Lorentz (1853-1928) on space-time, the discovery by the English physicist Joseph John Thomson (1856-1940) of a sub-atomic particle (later named the electron) and much else besides were pointing the way towards the physics of the twentieth century. In chemistry during the nineteenth century atomism was established (though not without considerable controversy), the modern system of chemical symbols was developed, and crucial concepts such as that of valency were enunciated. In the biological and earth sciences in 1800 most still thought in terms of special creation; by 1899, while there was still considerable dispute over the precise mechanism of evolution and over how much time needed to be allowed for the process, it was generally believed that evolution had occurred and that the earth was considerably older than apparently allowed for by the Bible.
