Tropical Africa escaped from the glaciers that covered the temperate parts of the world during the Ice Age. The legacy is that most of the parent materials of the soils of tropical Africa are old, highly weathered and devoid of bases and phosphate-bearing minerals. Traditional farming systems which were relatively stable and sustainable relied on long fallow periods after one to two years of cropping to maintain the productive capacity of the soils. In recent times and especially in densely populated areas, a sizeable class of 'landless' farmers have begun to cultivate marginal lands or to...

The NATO Advanced Research Workshop on "Paleoclimatology and Paleometeorology: Modem and Past Patterns of Global Atmospheric Transport" (held at Oracle, Arizona, USA from November 17-19, 1987) brought together atmospheric chemists, physicists, and meteorologists who study the origin and transport of modem-day mineral and biological aerosols with geologists and paleobotanists who study the sedimentary record of eolian and hydrologic processes along with modelers who study and conceptualize the processes influencing atmospheric transport at present and in the past. Presentations at the workshop...

Contemporaryphilosophyseems a great swirling almost chaos. Every situation must seem so at the time, probably because philosophy itself resists structura tion and because personal and political factors within as well as without the discipline must fade in order for the genuinely philosophical merits of performances to be assessed. Nevertheless, some remarks can still be made to situate the present volume. For example, at least half of philosophy on planet Earth is today pursued in North America (which is not to say that this portion is any less internally incoherent than the whole of which it...