his portfolio till such time as he should judge best to make it known. Being obliged to make his living by manual labor, Mercator selected the making of mathematical instruments, with the designing, engraving, and illumination of maps, as his business. He thus entered upon a career which he never left, and which was destined to bring him fortune and glory. In order better to qualify himself for doing this work, he began a thorough course of mathematics. He studied with Gemma le Frison, who was in the habit of giving lessons at his house to a number of high-born pupils, and practiced engraving with him. He made rapid progress, and was able in a short time, having been licensed by the university, himself to give lessons in geography and astronomy; and he made with a precision which was remarkable at that time the instruments which his pupils had to use. In 1541 he presented to Cardinal de Granville a very handsomely executed terrestrial globe, with which his Grace was so well pleased that he introduced the author of it to the Emperor Charles V. He afterward entered the service of that prince, but it is not exactly known in what particular capacity. He is styled in his epitaph imperatoris domesticus, but that merely signified that he was attached to the imperial household. He made for his Majesty two other globes, a celestial one of glass, and a terrestrial globe of wood, which were greatly admired as superior to any specimens that had been before produced. They were unfortunately destroyed in the wars by which the Low Countries were afterward overrun. In 1559 he removed to Duisburg, where the Duke of Juliers and Cleves was contemplating the establishment of a university, and had assigned an honorable position in it to Mercator. The duke conferred upon him the appointment and title of his cosmographer. He published at that place a large number of maps, but delayed the publication of his atlas for a considerable time, out of regard to his friend Ortelius, who had also prepared a set of maps, and through Mercator's accommodating spirit was given an opportunity to work off his stock without the embarrassment of competition. It is to Mercator and Ortelius that the world owes the enfranchisement of geography from the errors ingrafted upon it by Ptolemy; and the maps of these two fellow-workers were the most exact known till those of Guillaume de l'Isle and D'Anville were published.
Geography was in his time a mixture of facts and fancies, much of what was taught in it having no better authority than old-time traditions and the fabulous stories of travelers who addressed themselves more to exciting wonder than to telling the truth. Maps were in a worse condition than the descriptive accounts, and gave the most erroneous possible views of the relative situation of the various parts of the earth. It was Mercator's work, to adapt an expression of Malte-Brun's, to demonstrate the extreme imperfection of the systems of the ancients and provoke their abolition. Modern geography, this distinguished
