Remember the Rainforest 1
could be obtained for a reasonable price now demanded exorbitant prices, so that, having happily escaped the drought, we now had to fear hunger. The village is located in a shallow valley, between the foothills of the Serra de Itiuba. The inhabitants, among whom were relatively few Portuguese, try not only to raise cattle but also to grow cotton.
We left the village on March 8 and approached the Serra de Itiuba, gradually rising. Near Rodeador Farm, at Legua de Queimadas, we saw reddish gneiss
White granite with azurite
extending from N. N. E. to S. S. W.; in Bebedor, a league ahead, white granite, predominantly heading north sloping west, and south sloping east. The closer we came to the Serra de Itiuba, the more often the granite appeared, and instead of
the mica, a coarse prasio-green pistacite, sometimes scattered in granulation, now running along a strip of the rock. This supplemental component occurs to a large extent in this rock. Thin layers of leaf amphibian appear among the granite in many directions. In the marches through these foothills of gentle slopes, we were revived by some downpours; but, at dusk, when we landed near the Olhos d'Agua Farm, the heat again became oppressive, and it turned violet in the west, the sky threatening thunderstorms.
Clear waters of Olhos d'Agua
At seven o'clock, when it was already dark, a wind began to blow, which seemed to us to announce that the storm was breaking, so that, to secure the luggage against the rain, we soon hid it under the thicket. On this occasion, we had the opportunity to observe the most wonderful phenomenon that can draw the attention of botanists. The vegetation here consisted in part of a leafless shrub
(Euphorbia phosphorea), and when its branches were shaken and beaten violently by the luggage boxes and the passing of the mules, a white milk that shone in the moment of exudation sprouted from the bruises. I didn't want to believe what I saw until I scratched it myself, with sharp tips on the branches, causing the phenomenon. The phosphorescence lasted a few seconds at a time, and it was brighter than that of the rotten stick, yet less strong than the luminous aureola of the flowers. During this phenomenon, the thermometer indicated 20 ° R and Volta's electrometer showed no trace of atmospheric electricity. On many stalks and branches I always had the same result; but after one hour, when the temperature had dropped to 16 ° R., I could no longer notice that glow of light. Up to the Sao Francisco River, I found the plant in abundance, sometimes forming impenetrable dense hedges, but then I was no longer happy to observe the
Valley of Rio Sao Francisco