<P> By the 19th century, the study of science had come into the purview of professionals and institutions . In so doing, it gradually acquired the more modern name of natural science . The term scientist was coined by William Whewell in an 1834 review of Mary Somerville's On the Connexion of the Sciences . But the word did not enter general use until nearly the end of the same century . </P> <P> According to a famous 1923 textbook Thermodynamics and the Free Energy of Chemical Substances by the American chemist Gilbert N. Lewis and the American physical chemist Merle Randall, the natural sciences contain three great branches: </P> <P> Aside from the logical and mathematical sciences, there are three great branches of natural science which stand apart by reason of the variety of far reaching deductions drawn from a small number of primary postulates--they are mechanics, electrodynamics, and thermodynamics . </P> <P> Today, natural sciences are more commonly divided into life sciences, such as botany and zoology; and physical sciences, which include physics, chemistry, geology, astronomy and materials science . </P>

All measurements in science must have a number and a