Meteorological research is not characterized, to as great an extent as are many other fields of science, by prominent trends; that is, current meteorological literature is not in general dominated by discussions of any one particular topic or problem, but rather many widely different problems are constantly being subjected to investigations that are comparable in extent and that result in steady, even if not spectacular, progress throughout the field of meteorology. It occasionally happens, however, that for one reason or another an especially significant development takes place in connection with some particular problem, and for a time commands unusual attention. As past examples, there may be cited the striking development of the theory of turbulent motion in the lower atmosphere and its application to the explanation of a wide range of meteorological phenomena, which began with the work of G. I. Taylor in 1915; and the extensive work on the polar‐front theory of atmospheric circulations, initiated by the Norwegian meteorologists about 191