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The Sahara retreats
Satellite images taken this year and 20 years ago show that the desert is in retreat thanks to a resurgence of trees. They are mainly ana trees (Faidherbia albida), a type of acacia. Wherever the trees grow, farming can resume. Tree planting has led to the re-greening of as much as 3 million hectares of…
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Chinese inventions and the Needham Question
Gunpowder, printing, magnetic compass , silk, porcelain, as well as the breast strap and horse collar (massively i mproved efficiency of horse power eg for ploughing cf oxen). Not nearly as i mportant within China – gunpowder was not develop e d i nto weapons because politically very stable, printing was the exclusive skill of…