Most luckily for him at this time, a task was given him by government, for which he was well suited, and which brought him good pay. The king, Francis I., having had, like many another sovereign, some difficulty with his faithful subjects in the matter of imposts, now found it necessary to make a new regulation of taxes; and for this, among other things, an inspection of the salt marshes on the coasts of France was needed, in order to name the right sums for taxation, and a knowledge of arithmetic was required as well. Palissy was appointed; and to the great delight of his family, who thought that his mind would now be forever diverted from the search for enamel, he set forth to explore the islands and the shores of France. He drew admirable outlines of the forms of the salt marshes, and wrote with eloquence upon the sublimity of the sea. Ease and comfort came back. His task was ended; but debts were paid, and plenty of money remained. The first thing he saw on returning home, alas! was the cup,--his joy and despair. "How beautiful it is! how brilliant!" he exclaimed; and once more he threw himself into the pursuit of the elusive enamel. It was easy to see that the so much admired faience of Italy was simply common baked clay, covered with some substance glazed by heat, but so composed as to adhere to the surface after it had cooled. But what substance? He had tried all sorts of materials; why had none of them melted? Palissy at length decided that the fault had been in using the common potter's furnace. Since the materials were to be vitrified by the process, they should be baked like glass. He broke up three dozen pots, pounded up a great quantity of different ingredients, and spread them with a brush on the fragments; then he carried them to the nearest glass-works. He was allowed to superintend the baking himself; he put the specimens in the oven, and passed the night attending the fire. In the morning he took them out. "Oh, joy! Some of the compounds had begun to melt; there was no perfect glaze, only a sign that I was on the right road." It was, however, still a long and weary one. After two more years, Palissy was still far from the discovery of enamelling, but during this time he was acquiring much knowledge. From a simple workman he had become a learned chemist. He says himself, "The mistakes I made in combining my enamels taught me more than the things which came right of themselves."