enjoys in its complex articulation over the other continents. The passage in Strabo runs thus: “We begin with Europe, because it is so intricately organized, and is the most favorable for human culture, and has conferred upon the other continents the most of the advantages which its position has secured for itself. It is habitable almost everywhere; there is but a little portion of its territory too cold to be the home of man, etc. It enjoys an admirable physical conformation, for it is so perfectly harmonized in the mingling of plains and mountains, (ὅλη γάρ διαπεποίκιλται πεδίας τε και ὅρεδιν,) that the city and the country are brought together, and the people educated by equally favorable conditions to habits of great bravery. Europe is, therefore, complete in herself, (ἀμταρκεστάτη ἐστί.)” By this Strabo indicates the independent character of Europe, and its equality with the other continents, despite its smaller size. Yet for long centuries this insight of that keen observer into one of the most weighty of all the physical conditions of the globe was almost wholly overlooked. At length, however, Humboldt brought it out into new life in its climatological relations, and showed that it is one of the most important considerations to base a study of the distribution of plants and animals upon, as well as for the study of almost all kinds of physical phenomena. In his very instructive paper on the most prominent reasons for the variation in temperature on the globe, published in 1827, he uses the significant expression: “Our Europe is indebted for its mild climate, to its position, and its articulated form.” We have adhered to the same view, and have expanded it in a paper[7] called The Geographical Position and Horizontal Extension of the Continents, as well as in all my lectures. The Superficial Dimensions and Articulation of the Continents. We proceed from the more simple to the more complex forms, and begin, therefore, with Africa, which has the most uniform contour of all the continents. Africa, the true South of the earth, is distinguished from all the other great divisions of the earth by its almost insular form and its unbroken outline. It is separated from Asia merely by the Isthmus of Suez, scarcely 70 miles wide. But it is of altogether more virgin a nature than Asia, and has been encroached upon by scarcely any foreign influence. Africa is a unit in itself; the most exclusive of continents, its periphery is almost a perfect ellipse. With the exception of the single Gulf of Guinea on the west side, the continent is a true oval. Its linear dimensions are almost equal in length and breadth. It extends about 35° on each side of the equator, and is about 70° of longitude in width. The length and breadth are both about 5000 miles.