The question of the rivers had raised fresh obstacles, and the experts had brought matters to such a tangle that it was necessary in 1893 to draw up a Protocol to explain them further. The main principle which it fixed was that in case the high peaks of the Cordillera should be crossed by any river, that river should be cut by the boundary line. The experts continued their work, which was extremely arduous, for the boundary line ran through unexplored forests and mountains. But in 1895 feelings ran to a dangerous height in both countries, and the people of Argentina declared that the Chilians were assuming an aggressive attitude and were likely to attack them. They were made the more uneasy by the discovery that the army and stores had, like everything else, suffered from long years of misrule, and Congress voted fifty million gold dollars for military preparations. In July, 1898, a further controversy arose. The Puna de Atacama is a great salt waste of rugged tableland, volcanic, grassless, and inhospitable. Working from the north, the experts had found no great difficulty until they reached this savage territory. Here there was a deadlock, and the Chilians claimed the whole district. Possibly the belief that the disputed territory contained considerable borax deposits accentuated the quarrel, but the main source of it was national pride, for the majority of the Andine territory was of small value. The experts south of the Atacama waste proceeded more smoothly till they reached Patagonia. "Here,[56] indeed, the fundamental condition of identity between the "highest crest" and the "water parting" (or "divide," as it is called in North America), existed in full force, and no ground for dispute presented itself, the "main range" of the Andes being exceptionally well adapted by position and structure for an international boundary. It was the divergence of these two essential conditions in Patagonia which imperilled the peace of South America. The Patagonian rivers were found to flow from east to west right athwart, or transverse to, the general trend of the Andine mountain system from north to south. They were found to break across the great mountain masses, and to intersperse wide valleys, across which the boundary must either be carried from one mass of peaks to the next or else be made to skirt the indefinite edge of cordillera and pampas, where the two insensibly combine and where the rivers rise. A very little examination proved the incompatibility of "higher crests" with "water parting" as a fixed principle of demarcation in these parts."[57] With this fruitful field of dispute before them it is not surprising that angry feelings were engendered, especially among the Chilians, who have narrow territory, and were unwilling to give up a square mile without a struggle. In August Chile despatched an ultimatum demanding arbitration, and Roca induced his Cabinet to assent to the demand. [Illustration: BOUNDARY LINE IN THE ANDES.]