"Never you mind, old son," rejoined the Acting Chief. "In due course I'll enlighten your mind on the subject, but until then--nothin' doin'." For the next ten minutes conversation drifted into other channels. Peter had almost forgotten about the mysterious inquiries of Mr. Preston, when the latter inquired abruptly: "What do you think is our position, Sparks?" "About fifty miles west of Madagascar," replied Peter. The Acting Chief shook his head. "Wrong, my festive. Absolutely out of it," he stated with conviction. "Say a hundred and fifty miles to the south'ard of Cape St. Mary--that's the southern-most point of Madagascar--and you won't be far out." "But, why----?" began the astonished Wireless Officer. "Hold on," continued Preston. "It's now mid-summer in the Southern Hemisphere. Consequently the sun must be overhead, or nearly so, on the Tropic of Capricorn. Here, at midday, it's roughly five degrees north of our zenith. That means we're well south of the island you were making for." "But how's that?" demanded Mostyn. "I steered due east, and when the wind headed us I tacked for equal periods." "Maybe you did," rejoined the Acting Chief drily. "You don't know the deviation of the boat's compass. Neither do I, for that matter. It might be points out on an easterly course. Again, there's a strong current setting southward through the Mozambique Channel. Another and by no means inconsiderable factor is that almost every boat when close-hauled sails faster on one tack than the other. The net result is that, unconsciously, you were faced well to the south-east instead of making due east. However, here we are, and we must make the best of it. Everything considered, old man, you haven't done so badly." By dusk everything was in order so far as their limited resources permitted, even to the extent of building a light breastwork on the windward side of the camp to protect the tents from storms from seaward. The strenuous labours had kept the castaways' minds so fully occupied that they had had no time to think about their difficulties. Tired in body, yet cheerful in mind, they slept the sleep that only the healthy can enjoy. CHAPTER XXIX Repairs and Renewals At sunrise on the following morning Peter scaled the highest point of the island, hoping that in the clear air his range of vision would be increased sufficiently to make out land. He was disappointed. Nothing of the nature of land was in view. The horizon, clear and well defined, surrounded him in an unbroken circle. He was considerably troubled in his mind over the situation. Desert islands were all very well in their way, provided there was a chance of getting away from them. Evidently this island was well out of the regular steamer track, while sailing vessels, running between The Cape and India and the Federated Malay States, would pass well to the eastward in order to take full advantage of the monsoons.