I'm trying to gather background material for my next novel. Trouble is, I keep going off on tangents! My period is the 1914-18 war, but I'm now reading about slavery and David Livingstone's accounts of his exploration of the Zambesi Valley and Lake Nyasa. I'm currently reading about his journey from the coast, up the Rovuma River to Lake Nyasa. What an amazing man he was; such endurance. He wasn't very good at managing his expedition, but he kept moving on. Evidence of slavery was everywhere - Africans selling their own people. Village headmen selling their own villagers. Those who couldn't keep up were killed. The slaves were bought by Arabs. Not a European to be seen - at least in the Rovuma area. Probable ten thousand slaves were sold every year, but the casualty rate was huge.