My barometer, intended for taking the altitude of the principal botanical halts, soon becomes a pretext for attacks on the gourd with the rum. No sooner is a noteworthy plant observed than somebody cries: ‘Quick, let’s look at the barometer!’ And we all crowd around the gourd, the scientific instrument coming later. The coolness of the morning and our walk make us appreciate these references to the barometer so thoroughly that the level of the stimulant falls even more swiftly than that of the mercury. In the interests of the immediate future, I must consult Torricelli’s tube a little less often. As the temperature grows too cold for them, first the oak and the ilex disappear by degrees; then the vine and the almond-tree; and next the mulberry, the walnut-tree and the white oak. Box becomes plentiful. We enter upon a monotonous region extending from the end of the cultivated fields to the lower boundary of the beech-woods, where the predominant plant is Satureia montana, the winter savory, known here by its popular name of pébré d’asé, Ass’s pepper, because of the acrid flavour of its tiny leaves, impregnated with essential oil. Certain small cheeses forming part of our stores are powdered with this strong spice. Already more than one of us is biting into them in imagination and casting hungry glances at the provision-bags carried by the Mule. Our hard morning exercise has brought appetite and more than appetite, a devouring hunger, what Horace calls latrans stomachus. I teach my colleagues how to stay this rumbling stomach until they reach the next halt; I show them a little sorrel-plant, with arrow-head leaves, the Rumex scutatus, or French sorrel; and, practising what I preach, I pick a mouthful. At first they laugh at my suggestion. I let them laugh and soon see them all occupied, each more eagerly than his fellow, in plucking the precious sorrel. While chewing the bitter leaves, we come to the beeches. These are first big, solitary bushes, trailing on the ground; soon after, dwarf trees, clustering close together; and, finally, mighty trunks, forming a dense and gloomy forest, whose soil is a mass of rough limestone blocks. Bowed down in winter by the weight of the snow, battered all the year round by the fierce gusts of the mistral, many of the trees have lost their branches and are twisted into grotesque positions, or even lie flat on the ground. An hour or more is spent in crossing this wooded zone, which from a distance shows against the sides of the Ventoux like a black belt. Then once more the beeches become bushy and scattered. We have reached their upper boundary and, to the great relief of all of us, despite the sorrel-leaves, we have also reached the stopping-place selected for our lunch.