6. In case the region of disturbance of the indifferent (or adiabatic) equilibrium is very extensive, as, for example, the whole of the tropical zone, the temperature adjustment can no longer be accomplished by locally ascending whirls, and a whirling current must then arise involving the whole atmosphere. The same conditions apply to these as to the local whirls of accelerated upward motion and retarded descent in such a manner that the velocity at different altitudes arising from heat converted to work is approximately proportional to the prevailing pressure at the place. 7. In consequence of the meridional motion produced and maintained by conversion of heat into work, the whole atmosphere in every latitude must rotate with approximately the same absolute velocity. Thus the meridional currents produced by overheating combine with the currents embracing the whole {46} wind system of the earth, with the result of disseminating the excess of temperature and humidity of the torrid zone over the temperate and arctic zones, thereby producing the prevailing winds. 8. This is accomplished by the production of alternating local depressions and elevations of barometric pressure by the disturbance of indifferent equilibrium in the upper layers of the air. 9. "Highs" and "lows" are a consequence of the temperatures and velocities of the upper currents. Whence it follows that the most important problem of meteorology is the investigation of the causes and consequences of the disturbance of indifferent equilibrium of the atmosphere, and the weightiest problem in weather prediction is the investigation of the geographical origin or extraction of air currents pursuing their course above us toward the pole. * * * * * In Pomortsew's treatise on synoptic meteorology, published in Russia, there are full chapters on prediction of weather, whether from synoptic charts, from observations at a single place, or from prognostics of great length based on researches on the succession of warm and cold months. It also contains Pomortsew's investigations on the types of pressure distribution in eastern Europe, as well as the average path of cyclones. * * * * * The favorable opportunities afforded by the Eiffel tower have been utilized by French meteorologists. M. Angot states that during the anti-cyclone of November, 1889, the temperature on the tower was several degrees higher than below. The change of weather set in earlier, with a strong and warm wind, on the tower, while the air at the ground was cold and calm. Wind observations on the tower show a ratio of 3.1 at that height (303 meters) to the velocity at a height of 21 meters, as determined from 101 days' observations, which, remarkable at such a small height, discloses the peculiarity of high mountain stations. * * * * *