206 A TROPICAL DEPENDENCY must have drunk the water of Zem-Zem to be able to stand it," was the comment of one of Ahmed Baba's fellow-pupils on such an occasion. But Ahmed Baba, in faithful remembrance, forgets the impatience of youth, and keeps only admiration. " His like," he says, **will never be found again." The mind of this teacher is described as ** subtle, sagacious, ready, swift to comprehend. His intelligence was broad and luminous. His usual manner was taciturn and grave, but he would occasionally break into sallies of wit. He occupied himself with what concerned him, listened to no gossip, and took part in no frivolity, but "wrapped himself in a magnificent mantle of discretion and reserve. His hand held fast the standard of continence." In the atmosphere of laborious calm which is pictured by such a rule of existence, the sages of Timbuctoo would seem to have lived and carried on their labours to advanced old age. It is impossible not to be struck by the long periods of activity which are assigned to distinguished scholars. Ahmed Baba himself was born in 1556, and did not die till 1627, writing industriously during the greater part of his grown-up life. Nor was his career exceptional in this respect. Seventy, eighty, and even ninety, are ages at which men were still frequently to be found at work. The study of law, literature, grammar, and theology would seem to have been more general at Timbuctoo than that of the natural sciences. We hear, however, of at least one distinguished geographer, and allusions to surgical science show that the old maxim of the Arabian schools, ''He who studies anatomy pleases God," was not forgotten. At a later date (16 18) the author of the Tarikh incidentally mentions that his brother came from Jenne to Timbuctoo to undergo an operation for cataract at the hands of a celebrated surgeon there — an operation which was wholly successful. The appearance of comets, so amazing to Europe of the Middle Ages, is also noted calmly, as a matter of scientific interest, at Timbuctoo. Earth-