"Light up your homes, O fathers, For those young hero bands, Whose march is still through vanquished towns And over conquered lands, Whose valor, wild, impetuous In all its fiery glow, Pours onward like a lava-tide, And sweeps away the foe!"[28.22] XXIX FINAL MILITARY OPERATIONS January, 1847-April, 1848 At the north, after the Buena Vista campaign and the embarrassments growing out of it came to an end, Taylor probably wished, in what an officer called "his easy dog-trot fashion," to advance as far as San Luis Potosí, and retained troops urgently needed by Scott; but by the middle of June, 1847, he doubtless realized that effective operations on so long a line, especially through hostile and much of the way through barren territory, were impracticable, and advised that Scott's column alone should act on the offensive. A month later orders of a corresponding tenor were issued at Washington, and then some 3000 surplus troops of the northern army proceeded toward the capital, though too late, of course, to assist in the decisive struggle.[29.1] Valencia, during his brief stay at San Luis Potosí in the early summer of 1847, not only requested permission to move against Saltillo, but planned that General Filisola, aided by a brigade under Avalos, then lying at Matehuala, by Reyes, the comandante general of Zacatecas, and by Urrea--who still commanded the "brigade of observation," and could easily pass across the Sierra Madre from Tula--should threaten, if not attack, Saltillo and Monterey, and at least keep the Americans on the defensive. Some disquieting movements of these troops resulted; but Valencia was soon called to Mexico, and various difficulties, chiefly a lack of means resulting from the American occupation, proved fatal to this ambitious enterprise, besides hindering the Mexican preparations to receive Taylor at San Luis Potosí.[29.1]