Negotiations were commenced at once and were kept up vigorously between Mr. Trist and the commissioners appointed on the part of Mexico, until the 2d of September.  At that time Mr. Trist handed in his ultimatum.  Texas was to be given up absolutely by Mexico, and New Mexico and California ceded to the United States for a stipulated sum to be afterwards determined.  I do not suppose Mr. Trist had any discretion whatever in regard to boundaries.  The war was one of conquest, in the interest of an institution, and the probabilities are that private instructions were for the acquisition of territory out of which new States might be carved.  At all events the Mexicans felt so outraged at the terms proposed that they commenced preparations for defence, without giving notice of the termination of the armistice.  The terms of the truce had been violated before, when teams had been sent into the city to bring out supplies for the army.  The first train entering the city was very severely threatened by a mob.  This, however, was apologized for by the authorities and all responsibility for it denied; and thereafter, to avoid exciting the Mexican people and soldiery, our teams with their escorts were sent in at night, when the troops were in barracks and the citizens in bed.  The circumstance was overlooked and negotiations continued.  As soon as the news reached General Scott of the second violation of the armistice, about the 4th of September, he wrote a vigorous note to President Santa Anna, calling his attention to it, and, receiving an unsatisfactory reply, declared the armistice at an end.

General Scott, with Worth’s division, was now occupying Tacubaya, a village some four miles south-west of the City of Mexico, and extending from the base up the mountain-side for the distance of half a mile.  More than a mile west, and also a little above the plain, stands Molino del Rey.  The mill is a long stone structure, one story high and several hundred feet in length.  At the period of which I speak General Scott supposed a portion of the mill to be used as a foundry for the casting of guns.  This, however, proved to be a mistake.  It was valuable to the Mexicans because of the quantity of grain it contained.  The building is flat roofed, and a line of sand-bags over the outer walls rendered the top quite a formidable defence for infantry.  Chapultepec is a mound springing up from the plain to the height of probably three hundred feet, and almost in a direct line between Molino del Rey and the western part of the city.  It was fortified both on the top and on the rocky and precipitous sides.