A chance suggestion made by Mr. Hampton had taken root. If the spies, as now was apparent, had betrayed the revolutionists’ plans, then the Oligarchs would not be looking for attack from Korakum along the subterranean river. Therefore, Mr. Hampton had suggested the possibility of making such an attack at a later date in conjunction with an attack in force from the field. “They expect,” he told the boys, “to be able to raise a considerable army of ten thousand or more countrymen, for the country groans under the misrule of the Oligarchs and is ripe for revolution. It awaits only the coming of a leader supported by determined captains, and in Captain Amanassar and his hundred men I feel certain such leaders have been found.” Accordingly, it had been decided not to abandon Korakum entirely, but to place a guard over the subterranean river for the purpose of capturing any Janissaries who might negotiate its passage from the interior, and of retaining control of that underground water thoroughfare to Athensi. Mr. Hampton, the boys and the Arabs were to form a portion of this guard, as Jack’s father had assured Captain Amanassar he would co-operate with the revolutionaries, at least as long as there was a possibility of effecting Bob’s rescue. “It is pretty certain,” he explained, “that Bob was captured to participate in the Sacrificial Games. Such being the case, his life will be jealously guarded until the time of the Games arrives. That gives us a full month more. Certainly, some way of saving him will develop in that time. Perhaps, the revolutionists will be successful and then, of course, the men destined to participate in the Games will be set free.” Jack and Frank could do nothing except acquiesce gloomingly. “But think of Bob’s feelings all that time, as he sees the end draw nearer with no word of hope from us,” said Frank. “Maybe,” added Jack “when he is in prison he will be able to rig up his radio set and we can send him a message of comfort, something to tell him we are working to rescue him.” “Maybe,” said Frank, sadly. “But we wouldn’t know whether he got our message or not. Well, come on. If it’s back to Korakum, we’ll finish putting the radio apparatus in shape.” Side by side, silent, each immersed in sad thoughts, Jack and Frank led the way on the return, followed by their companions. CHAPTER XIX. AT LOW EBB. Now began a period of waiting, during which the boys saw little of Jepthah. A guard of ten revolutionists was sent back to Korakum to supplement their own force under command of a cheery young man named Horeb who, like Jepthah, had served in the British Sudanese army, and had a good command of English. Thus the two parties had a common medium of expression. From Horeb, who each day sent a messenger to the main body, they received fragmentary accounts of the progress of events in the field.