Distrusting Taylor, and profoundly alarmed about the situation on the frontier,[9.26] Polk sent for Scott on May 13, and conferred upon him verbally the chief command in Mexico; yet, while admitting that he saw proofs of experience in the General's remarks, he pronounced him too "scientific and visionary," as the master of a difficult business must always appear to the tyro.[9.27] Probably he knew that a man could not become a soldier overnight, as he could become a militia colonel or a "statesman," or--in Santa Anna's opinion--a professor of jurisprudence; but he believed that, should fighting really need to be done, even an improvised army would make "a brisk and a short war of it," as the administration paper neatly said, and, if necessary, dictate a peace "in the Halls of the Montezumas." Under circumstances like these prevision and science appeared rather superfluous. The only things needful were to march now and triumph to-morrow.[9.30] Scott, however, felt that waging war might involve military operations. He undertook to prove by elaborate calculations that the greater part of the volunteers could not at the best arrive on the Rio Grande before the first week in August; and, since that would be the rainy season, when the hoofs of mules and horses would be unfit for hard use, and various other difficulties would arise, he recommended that most of the new troops, after remaining under instruction at salubrious points in the United States during the summer, should be placed upon that river by September 25, so as to make, with the volunteers and regulars already there, 25,000 or possibly 30,000 healthy, properly equipped and more or less trained soldiers, ready to invade Mexico in a decisive manner. In the execution of this plan he did not intend to shirk or dally.[9.28] May 15 he gave the chiefs of the general staff directions about throwing supplies of all kinds upon the various rendezvous in advance of the volunteers, prompted the quartermaster general to obtain wagons, and even called attention to the necessity of seasonably obtaining light boats for the navigation of the Rio Grande.[9.30] His feeling was, however, particularly after news of what he called Taylor's "great and brilliant victories" arrived, that it would not seem proper--especially to military men--for him to supersede that officer except with heavy reinforcements; and no doubt he saw it would scarcely enhance a prestige that was dear to him personally and invaluable to him as the commander-in-chief, to lie idle in hot mud for several months. He therefore proposed to leave Washington about May 30, give his personal attention to the troops and supplies _en route_ and at the rendezvous, and reach the scene of action a little before them.[9.30]