As the two men tramped on, the streams began to drain to the west and the land grew more fertile, till one hundred and fifty miles from Kaze they began to ascend the slope of mountains overhanging the northern half of Lake Tanganyika. "This mountain mass," says Speke, "I consider to be the True Mountains of the Moon." From the top of the mountains the lovely Tanganyika Lake could be seen in all its glory by Burton. But to Speke it was a mere mist. The glare of the sun and oft-repeated fever had begun to tell on him, and a kind of inflammation had produced almost total blindness. But they had reached the lake and they felt sure they had found the source of the Nile. It was a great day when Speke crossed the lake in a long canoe hollowed out of the trunk of a tree and manned by twenty native savages under the command of a captain in a "goatskin uniform." On the far side they encamped on the opposite shore, Speke being the first white man to cross the lake. Having retired to his hut for the night, Speke proceeded to light a candle and arrange his baggage, when to his horror he found the whole interior swarming with black beetles. Tired of trying to brush them away, he put out his light and, though they crawled up his sleeves and down his back, he fell asleep. Suddenly he woke to find one crawling into his ear, and in spite of his frantic efforts it crept in farther and farther till it reached the drum, which caused the tired explorer intense agony. Inflammation ensued, his face became drawn, he could with difficulty swallow a little broth, and he was quite deaf. He returned across the lake to find his companion, Burton, still very ill and unfit for further exploration. So Speke, although still suffering from his ear, started off again, leaving Burton behind, to find the great northern lake spoken of as the sea of Ukerewe, where the Arabs traded largely in ivory. There was a great empire beyond the lake, they told him, called Uganda. But it was July 1858 when the caravan was ready to start from Kaze. Speke himself carried Burton's large elephant gun. "I commenced the journey," he says, "at 6 p.m., as soon as the two donkeys I took with me to ride were caught and saddled. It was a dreary beginning. The escort who accompanied me were sullen in their manner and walked with heavy gait and downcast countenance. The nature of the track increased the general gloom.