on February 17—21 arrived at La Encarnación, nearly 200 miles from San Luis.[1] Several thousand men had been lost from death, sickness or desertion on the way. Others had been detached at various points, and Miñón had now placed himself at Potosí hacienda behind the mountains on Taylor‘s left; but on February 19 the figures for the army were 15,142 officers and men[2]—general the strongest and most determined that had set 
out—and a brilliant review, held the next day, showed no lack of confidence and enthusiasm. A triumph was considered certain.[3]
Santa Anna had supposed that a part of the American army occupied La VaquerÍa, some eight or ten miles west of Taylor’s actual position, and his intention had been to surprise it; but by February 11 he learned that all had concentrated at Agua Nueva. He now had the choice of three routes. One was the direct road to that point; the second would have taken him via La Hedionda to the rear of Buena Vista; and the third ran by the way of La Vaquería to the north of Agua Nueva.[4] Santa Anna desired, he said later, to pursue one of the lateral routes, and place himself between Taylor and Saltillor; but both of these routes were said to be circuitous, difficult if not impracticable for artillery, and perhaps inadequately supplied with water and provisions. He decided therefore to surprise Agua Nueva, believing that should his forces be seen, they would be regarded as a part of Miñón’s brigade.[5]
That general was ordered to proceed via La Hedionda to the American rear, and a little after noon on February 21—every soldier having been ordered to drink his fill, carry all the water
