One of the most dramatic advances in the physical sciences during the nineteenth century was the emergence of spectroscopy. It rapidly became an invaluable experimental technique for chemists and astronomers, while for physicists it opened a window upon the world of sub-atomic phenomena. Sir John Herschel played an important part, the value of which has sometimes been underestimated, in the early development of spectroscopy. This paper examines his contribution to the subject during the period 1819–61 in the light of his (...) publications and of certain manuscript material preserved in the Royal Society's Library. Herschel corresponded with most of the scientists who did important work in spectroscopy during his lifetime, and he expressed definite opinions on most of the practical and theoretical problems that arose in it; however, the present study cannot pretend to offer a complete discussion of all aspects of the early history of spectroscopy. (shrink)

In the early nineteenth century, Norwegian mathematician and astronomer Christopher Hansteen (1784–1873) contributed significantly to international collaboration in the study of terrestrial magnetism. In particular, Hansteen was influential in the origin and orientation of the magnetic lobby in Britain, a campaign which resulted in a global network of fixed geomagnetic observatories. In retrospect, however, his contribution was diminished, because his four-pole theory inUntersuchungen der Magnetismus der Erde(1819) was ultimately refuted by Carl Friedrich Gauss inAllgemeine Theorie des Erdmagnetismus(1839). Yet Hansteen's main (...) contribution was practical rather than theoretical. His major impact was related to the circulation of his instruments and techniques. From the mid-1820s, ‘Hansteen's magnetometer’ was distributed all over the British Isles and throughout the international scientific community devoted to studying terrestrial magnetism. Thus in the decades before the magnetic crusade, Hansteen had established an international system of observation, standardization and representation based on measurements with his small and portable magnetometers. (shrink)