In 1878 appeared Dick Sand: A Captain at Fifteen, an epic story of the slave trade. This picture of the wilds of Africa, its adventures and its dangers, the savage hunting both of beasts and men, has always been a favorite among Verne's readers. It contains no marvels, no inventions, but merely, amid stirring scenes and actions seeks to convey two truthful impressions. One is the traveler's teaching the geographical information, the picture of Africa…