On the 11th, the work of locating and opening the road along the line of investment was continued, the working party being still a good deal annoyed by both infantry and artillery fire. At 1 P. M., I reported to General Patterson that the road was opened, through the chaparral, to the bare sand hills. He ordered me to report, with the engineer company, to General Worth; and the latter directed me to report to the General Headquarters. On the same day I was ordered by Colonel Totten, Chief Engineer, to find and cut off the underground-aqueduct which conveyed water into Vera Cruz. That business was effectually accomplished by the engineer company on the 13th.[2] From that time, until the commencement of work upon the batteries and trenches, the engineer company and its officers were engaged in reconnoitring the ground between the picket line of our army and the fortifications of the city. My reports were made each night to the Chief Engineer. The night of the 15th, he pointed out to me, on a map of the city and its fortifications, the general location in which it was desired to place the army gun battery, on the southern prolongation of the principal street of the city, and within about six hundred yards of its fortifications. He directed me, with the engineer company, to closely examine that ground. I was informed by him, at the same time, that Captain R. E. Lee, of the engineer corps, had discovered a favorable position for a battery, of six heavy naval guns, on the point of a commanding sand ridge, about nine hundred yards from the western front of the city; but no final decision would be made in regard to the naval battery until the army battery could be definitely located. He said General Scott was getting impatient at the delay; and I was directed to find, as soon as possible, a position that would satisfy the conditions prescribed, by the Chief Engineer, for an army battery. I explained those conditions to McClellan and to Foster; and informed them that I would assign one-third of the company to each of them as an escort--take one-third myself--and we would all three start, at daylight next morning, in search of a location for the required battery. It was necessary that we should be extremely careful not to get to fighting each other in the dense chaparral. We found a location that complied with the conditions. In reporting this fact to the Chief Engineer, I added: "The communication with the battery will be very difficult--will require a great deal of work--and will be dangerous". He ordered me to take the engineer company to the selected ground, next morning, and lay out the battery; and said he would direct Lieutenant G. T. Beauregard, who had supervised the construction of the field fortifications at Tampico, to assist in the work.