On the evening of the 15th they returned permanently to the Chimneys, bringing the rest of the pottery back with them, and putting out the oven fire until there should be use for it again. This return was marked by the fortunate discovery by the engineer of a substance that would answer for tinder, which, we know, is the spongy, velvety pulp of a mushroom of the polypore family. Properly prepared it is extremely inflammable, especially when previously saturated with gunpowder, or nitrate or chlorate of potash. But until then they had found no polypores, nor any fungi that would answer instead. Now, the engineer, having found a certain plant belonging to the mugwort family, to which belong wormwood, mint, etc., broke off some tufts, and, handing them to the sailor, said:— “Here, Pencroff, is something for you.” Pencroff examined the plant, with its long silky threads and leaves covered with a cotton-like down. “What is it, Mr. Smith?” he asked. “Ah, I know! It’s tobacco!” “No,” answered Smith; “it is Artemesia wormwood, known to science as Chinese mugwort, but to us it will be tinder.” This mugwort, properly dried, furnished a very inflammable substance, especially after the engineer had impregnated it with nitrate of potash, which is the same as saltpetre, a mineral very plenty on the island. This evening the colonists, seated in the central chamber, supped with comfort. Neb had prepared some agouti soup, a spiced ham, and the boiled corms of the “caladium macrorhizum,” an herbaceous plant of the arad family, which under the tropics takes a tree form. These corms, which are very nutritious, had an excellent flavor, something like that of Portland sago, and measurably supplied the place of bread, which the colonists were still without. Supper finished, before going to sleep the party took a stroll upon the beach. It was 8 o’clock, and the night was magnificent. The moon, which had been full five days before, was about rising, and in the zenith, shining resplendent above the circumpolar constellations, rode the Southern Cross. For some moments the engineer gazed at it attentively. At its summit and base were two stars of the first magnitude, and on the left arm and the right, stars, respectively, of the second magnitude and the third. Then, after some reflection, he said:— “Herbert, is not to-day the 15th of April?” “Yes, sir,” answered the lad. “Then, if I am not mistaken, to-morrow will be one of the four days in the year when the mean and real time are the same; that is to say, my boy, that to-morrow, within some seconds of noon by the clocks, the sun will pass the meridian. If, therefore, the weather is clear, I think I will be able to obtain the longitude of the island within a few degrees.” “Without a sextant or instruments?” asked Spilett.