From earliest times the rainbow had delighted and puzzled observers. Men invented myths to explain the beautiful arc of multicoloured light that appeared after the rain. But a scientific answer to the puzzle of the rainbow did not come until 1666. In that year Sir Isaac Newton began investigating the problem of eliminating the colour [...]

  Study of the lines in various spectra has helped build the modern theory of matter. Soon after Bunsen and Kirchhoff developed the use of spectral lines as a means of chemical analysis, scientists thought that the various lines were given off by atoms vibrating at different rates under the stimulus of heat. They believed [...]

Moseley, Henry Gwyn-Jeffreys (1887-1915), British physicist, born in Weymouth, England; gave his name to the Moseley number. In 1913 and 1914 the English physicist H.G.J. Moseley (1887-1915) announced the discovery of far-reaching relations among X rays produced from the surfaces of different metals by the impact of electrons. He found that each metal gives certain [...]

The total number of people, plants, and animals in the world is smaller than the total number of insects in the world. Although over 800,000 insects have been described and named, there are still so many different kinds of insects on earth that scientists have named fewer than half of them. There are so many [...]