The discovery of fronts, the more or less sharp boundaries between unlike wind-streams, with their associated cloud-belts and weather, and their role in the development of cyclones (barometric depressions) was made by the Norwegian school of meteorologists under Professor Vilhelm Bjerknes at Bergen in 1917 and expounded in a series of scientific papers, now regarded as classics of the subject, over the years that followed (e.g. J. Bjerknes 1919, 1922; V. Bjerknes et. al. 1933). Some of the related atmospheric structures showing convergence and uplift of one of the two air currents meeting at a boundary had been spotted much earlier, notably by Loomis in 1840-1 in the USA, and by Shaw and Lempfert in Britain in 1905-6, but their full significance had not come out.