Outside the Tucuman district an unfortunate attempt was made to plant the sugar industry at Santiago del Estero, and large works were constructed. But the frost is severe there. For some years they tried to keep the Santiago works going with cane brought from Tucuman, but the freight was too heavy, and the works had to be abandoned, or else dismantled and set up elsewhere. The valley of the Rio Grande, from Jujuy to 200 miles north of Tucuman, in the sub-Andean depression between the Sierra de Zenta and the Lumbrera, has, on the other hand, suitable conditions for the cultivation of the cane. Frost is rare. The climate is warmer than at Tucuman, the canes ripen more quickly, and the average return is higher. The water-supply also is good. There have long been plantations in this region. Their first market was the region of the tableland and the valleys, where they chiefly sold brandy: a traffic of long standing, which one always finds round the cold districts of the Andes, from Colombia to the north of Argentina. The modern refineries of Ledesma and San Pedro took the place of the primitive mills as soon as the railway approached Jujuy, and even before it entered the valley of the Rio Grande. They then sent their sugar by waggon in November and December, between the close of the sugar season and the commencement of the rains, which spoil the roads. The sugar district of Jujuy now has a very different economic and social organization from that of Tucuman. Here there are no farmer-proprietors. Each centre is a large estate, in the midst of the forest, where the workers are lodged and fed by the works that employs them. The contractors who clear the ground for them are obliged by the terms of their contract to import their workers directly from the south, so that they will not take any away from the farming. There is no available labour, no free market, on the spot. Since the completion of the Quebrada de Humahuaca line, however, there has been a good deal of immigration, to settle or temporarily, of the mountaineers of the tableland. The sphere of influence of San Pedro now extends as far as Bolivia. For the harvest, which, like that of Tucuman, requires a good deal of additional manual labour, the works look to the wild Indians of the Chaco. This curious stream of seasonal migration, which the sugar campaign of Jujuy provokes every winter outside the zone of white colonization, is of very old date, going back more than sixty years. Belmar notices it about the middle of the nineteenth century. The recruiting agents of San Pedro and Ledesma set out from Embarcacion, where the railway ends, and enter the Chaco, from which each of them brings a troop of some hundreds of natives between March and June. The number of these temporary immigrants seems to be about 6,000. The Chiriguanos of the north leave their families on the Chaco, and the men come alone. The Matacos immigrate in whole tribes. They camp in huts