1874, after the delivery of the Chilean ironclad Almirante Cochrane and the ironclad Blanco Encalada, the Argentine Senate postponed the matter until late 1874, and Sarmiento was prevented signing the treaty. Consequently, Argentina remained neutral during the war; and the Argentinians signed a Border Treaty with Chile in 1881. Claims on Patagonia Border disputes continued between Chile and Argentina, as Patagonia was then a largely unexplored area. The Border Treaty of 1881 established the line of highest mountains dividing the Atlantic and Pacific watersheds as the border between Argentina and Chile. This principle was easily applied in northern Andean border region; but in Patagonia drainage basins crossed the Andes. This led to further disputes over whether the Andean peaks would constitute the frontier (favoring Argentina) or the drainage basins (favoring Chile). Argentina argued that previous documents referring to the boundary always mentioned the Snowy Cordillera as the frontier and not the continental divide. The Argentine explorer Francisco Perito Moreno suggested that many Patagonian lakes draining to the Pacific were in fact part of the Atlantic basin but had been moraine-dammed during the quaternary glaciations changing their outlets to the west. In 1902, war was again avoided when British King Edward VII agreed to mediate between the two nations. He cleverly established the current Argentina-Chile border in Patagonia by dividing many disputed lakes into two equal parts. Several of these lakes still have different names on each side of the frontier, such as the lake known in Chile as Lago O'Higgins and in Argentina as Lago San Martín. A dispute that arose in the northern Puna de Atacama was resolved with the Puna de Atacama Lawsuit of 1899. Arms race and foreign policy cooperation Dreadnought race At the start of the 1900s a naval arms race began amongst the most powerful and wealthy countries in South America: Argentina, Brazil and Chile. It began when the Brazilian government ordered three formidable battleships whose capabilities far outstripped older vessels after the Brazilian Navy found itself well behind the Argentine and Chilean navies in quality and total tonnage. Baltimore Crisis During the Baltimore Crisis which brought Chile and the United States to the brink of war in 1891 (at the end of the 1891 Chilean Civil War), the Argentine foreign minister Estanislao Zeballos offered the US-minister in Buenos Aires the Argentine province of Salta as base of operations from which to attack Chile overland.