Thanks to its isolated position, which leaves it freely exposed on every side to atmospheric influence; thanks also to its height, which makes it the topmost point of France within the frontiers of either the Alps or Pyrenees, our bare Provençal mountain, Mont Ventoux, lends itself remarkably well to the study of the climatic distribution of plants. At its base the tender olive thrives, with all that multitude of semiligneous plants, such as the thyme, whose aromatic fragrance calls for the sun of the Mediterranean regions; on the summit, mantled with snow for at least half the year, the ground is covered with a northern flora, borrowed to some extent from arctic shores. Half a day’s journey in an upward direction brings before our eyes a succession of the chief vegetable types which we should find in the course of a long voyage from south to north along the same meridian. At the start, your feet tread the scented tufts of the thyme that forms a continuous carpet on the lower slopes; in a few hours they will be treading the dark hassocks of the opposite-leaved saxifrage, the first plant to greet the botanist who lands on the coast of Spitzbergen in July. Below, in the hedges, you have picked the scarlet flowers of the pomegranate, a lover of African skies; above you will pick a shaggy little poppy, which shelters its stalks under a coverlet of tiny fragments of stone and unfolds its spreading yellow corolla as readily in the icy solitudes of Greenland and the North Cape as on the upper slopes of the Ventoux. These contrasts have always something fresh and stimulating about them; and, after twenty-five ascents, they still retain their interest for me. I made my twenty-third in August 1865. There were eight of us: three whose chief object was to botanize and five attracted by a mountain expedition and the panorama of the heights. Not one of our five companions who were not interested in the study of plants has since expressed a desire to accompany me a second time. The fact is that the climb is a hard and tiring one; and the sight of a sunrise does not make up for the fatigue endured.