Neb and Pencroff had taken the fat from the dugong, which had been placed in large earthen jars. It was necessary to separate the glycerine from this fat by saponifying it. It was sufficient, in order to do this, to treat it with chalk or soda. Chalk was not wanting, but by this treatment the soap would be calcareous and useless, while by using soda, a soluble soap, which could be employed for domestic purposes, would be the result. Cyrus Smith, being a practical man, preferred to try to get the soda. Was this difficult? No, since many kinds of marine plants abounded on the shore, and all those fucaceæ which form wrack. They therefore gathered a great quantity of these seaweed, which were first dried, and, afterwards, burnt in trenches in the open air. The combustion of these plants was continued for many days, so that the heat penetrated throughout, and the result was the greyish compact mass, long known as “natural soda.” This accomplished, the engineer treated the fat with the soda, which gave both a soluble soap and the neutral substance, glycerine. But this was not all. Smith wanted, in view of his future operations, another substance, nitrate of potash, better known as saltpetre. He could make this by treating carbonate of potash, which is easily extracted from vegetable ashes, with nitric acid. But this acid, which was precisely what he wanted in order to complete his undertaking successfully, he did not have. Fortunately, in this emergency, Nature furnished him with saltpetre, without any labor other than picking it up. Herbert had found a vein of this mineral at the foot of Mount Franklin, and all they had to do was to purify the salt. These different undertakings, which occupied eight days, were finished before the sulphate of iron was ready. During the interval the colonists made some refractory pottery in plastic clay, and constructed a brick furnace of a peculiar shape, in which to distil the sulphate of iron. All was finished on the 18th of May, the very day the chemical work was completed. The result of this latter operation, consisting of sulphate of iron, sulphate of alumina, silica, and a residue of charcoal and cinders, was placed, in a basin full of water. Having stirred up the mixture, they let it settle, and at length poured off a clear liquid holding the sulphates of iron and alumina in solution. Finally, this liquid was partly evaporated, the sulphate of iron crystalized, and the mother-water was thrown away. Smith had now a quantity of crystals, from which the sulphuric acid was to be extracted.