"Peace, brother," said the man. "How was I to know? His beard is not yet grown. Allah is great! All the sahibs are men, even in the cradle." CHAPTER THE THIRTEENTH THE REVOLT OF THE KALMUCK MINERS While Lawrence was thus making his first essays in an apprenticeship to soldiering, his brother had found work to do which outran the little military experience he had gained. After giving Lawrence the signals agreed on, Bob steered straight up the valley. His mind was very busy during the half-hour’s flight to the mine. The management of the aeroplane had become so much a matter of habit and instinct that he was able to give a good deal of attention to his thoughts and imaginings. Telling Fazl to keep a good look-out, he sought to grapple with the strange problems so suddenly thrust upon him. First and greatest of them all was the meaning of the concentration of troops at the mouth of the valley. He dismissed as patently absurd the idea that their objective was his uncle’s mine. The gathering of so large a force for so trifling an end would be like employing a steam-hammer to crack a nut. He could not avoid the conclusion that their presence was quite independent of Nurla Bai, though on the other hand Nurla Bai’s actions had probably been calculated with the knowledge or suspicion that a body of his countrymen was at hand. What then was the explanation of the muster? The direction of their march, and the fact that they had thrown forward an advanced guard into the valley itself, seemed to indicate an intention to proceed through the valley to some further goal. What was that goal? He remembered the intelligence that had come in at odd times, of a levy _en masse_ of the Mongols, and his uncle’s suspicion that the Mongolian prince was meditating an attack on Russia. But this was not the way to Russia. Could it be that Afghanistan was the object of an invasion? Bob’s knowledge of the geography of the region was not very extensive, but he knew that, if Afghanistan was their objective, this valley was one of the most toilsome and indirect routes they could have chosen. The passes of the Hindu Kush to the westward offered few or no obstacles to an invading force; it was by these passes that the Mongolian hordes had always made their inroads, from the earliest times. Not only would the nature of the valley render the advance of a large army extremely arduous and prolonged; if the invaders should traverse it successfully, they would find themselves at what was probably the most intricate and inaccessible portion of the Amir’s dominions. It would be like marching from London to Chester through the Welsh mountains, with every difficulty monstrously exaggerated. Wellington’s passage of the Pyrenees was a slight operation compared with it.