Rawlinson himself attributed his triumph to his familiarity with the local Persian dialects; it was his intimate knowledge of the languages spoken by the peasants and tribes of Persia that enabled him to get to the root of many of the words which so sorely puzzled him. By the time he managed to obtain his copy of the Babylonian inscription through the aid of the little Kurdish boy, he had already wrested the secret from the Persian inscription, and his book had been published a year. He found the clue to cuneiform in the name of two kings, just as Young found his first clue in the name of Ptolemy. Before he bent his energies on deciphering the Behistun inscriptions, he had closely studied two other inscriptions which were identical but for two words. Rawlinson, puzzling over these words, at length concluded they were the names of two kings, that one king was the father and the other the son. He reasoned correctly, and thus obtained a clue to the inscriptions at Behistun, the deciphering of which ranks as one of the greatest achievements of the human brain. [Illustration: _By courtesy of the British Museum_ A RARE PHOTOGRAPH OF THE ROCK SCULPTURES AT BEHISTUN, SHOWING DARIUS THE GREAT RECEIVING CAPTIVES OF WAR] Over five hundred years before the birth of Christ, Darius, King of Persia, caused an account of his campaigns to be engraved on the rock in Persian, Babylonian and Median, so that all men who passed that way might read of the deeds of the great king. A full-length portrait of the monarch was carved in stone for posterity to gaze on his features, and to add to his glory he was shown receiving some of the prisoners captured in his campaigns. The remarkable skill shown by the Persian king in selecting the site is proved by the fact that the figures still exist, in spite of the storms beating on them for two thousand four hundred years. Darius was not ignorant of human nature. He knew full well the tendency of man to destroy. To defeat this tendency he had the rock cut away sheer to the foot of the cliff, while to preserve his inscription from the ravages of time he caused it all to be brushed with a sort of yellow varnish, a varnish of such unique quality that some of it protects the stone to this very day. We know much, can do many things. We fly in the air, tunnel the mountains, travel beneath the sea. Yet there is still a little that is hidden from us; and one thing of which we remain ignorant is the secret of that old Persian varnish, which will endure frost and hail and rain and shine for twenty-four centuries. CHAPTER X