Arabia, the country that has changed so little in a thousand years, has now seen the invasion of motor-caravans and aeroplanes. and oil pipe-lines - with what ultimate results it is not yet possible to see. But whatever may be its future, its past is secure in the possession of the language of the Koran, one of the most important in Islam: of a long roll of poetry and philosophy, of Greek science preserved when Europe was submerged by the barbarians, and of the Arabesque design. The culture of Arabia is less familiar to us than that of India or of China, with which Sir Denison Ross has already dealt in this series, but this will not be the least interesting of his talks.