Ramon Diaz considered the matter. He realized that he was in a position to refuse to grant permission. But at the same time, it was too early to show himself in his true colours. He had to make more use of the Englishman's undoubted skill before Rioguay was in a position to throw down the gauntlet to the British Empire. And Señor Strong's request was not unreasonable. He was supposed to be a free agent in the employ of the Rioguayan Government. To thwart him might cause trouble. He had not asked to go for a holiday to San Benito or anywhere in that direction. He wished to go up-country into the wilds beyond which was an impassable mountain chain, or at least impassable except with a train of mules to carry provisions and stores for a prolonged and perilous trek. No, there was no risk as far as Don Ramon was concerned. The Englishman would still be a prisoner in Rioguayan territory. "Very good, Señor Strong," he said. "We can spare you for ten days. I hope you have good sport. Of course, if you like, we will send along a flying-boat to see how you fare in case your boat meets with a mishap and you are stranded." "I should be delighted, Señor Diaz," replied Brian, without as much as a flicker of his eyelids. "Say in a week's time. She would be quite able to spot us up the Rio Tinto. I do not suppose we'll ascend for more than thirty kilometres." The two parted, Ramon Diaz shaking hands with himself at the prospect of being able to verify his suspicions as to what Señor Strong's secret invention actually was; Brian chuckling with satisfaction at the thought that he had bluffed the Rioguayan so neatly. Early next morning, the two Englishmen started on their dash for freedom. The final preparations took but little time, compared with the many hours spent in stealth to collect the essential portions of the secret ray apparatus. The latter, wrapped in oiled silk, were hidden in bags containing provisions, the smaller and intricate pieces being concealed in empty cartridge-cases and placed in Brian's ammunition belt. They took complete camp equipment, not that they had any idea of travelling on foot with it, but chiefly to lend colour to the deception that they were on a shooting expedition. Heavily-soled boots, leggings, change of socks and underclothing, sleeping-bags, and small mosquito nets, formed their travelling luggage. For defence and as a means of procuring food Brian carried a twelve-bore double-barrelled shot-gun, Peter an Express magazine rifle. In addition, they each had a 230 automatic pistol. Brian Strong had already handed over the keys and given final instructions to the acting manager, an intelligent Rioguayan, who had more black blood in his veins than white. The peons carried the gear down to the little landing-stage of the estate, where a small half-tide backwater communicated with the wide estuary of the Rio Guaya. "There's our boat," announced Brian.