The final maturing of the project of an infiltration gallery in San Geronimo as a low-pressure gravity supply, the division of the city into high- and low-pressure districts corresponding to the two supplies, with one reservoir, instead of two to the south of the city, and the other to the west at the Obispado, the entire details of both these gravity schemes, and of the whole sewage disposal scheme, as well as the modification introduced into the city work for the northern half, are unquestionably due to Mr. Conway, independently of the general views which may have been held on those points by other engineers. In March, 1910, Mr. Conway left Monterrey, all the principal works being finished. Since that time Vicente Saucedo, Assoc. M. Am. Soc. C. E., has put in many additional water mains and sewers in the northern part of the city, and is finishing the _force majeure_ work caused by the destruction wrought in the districts along the river banks by the extraordinary floods. The writer, having had an opportunity to watch the earnest efforts of the several engineers connected with these works, in the course of their design and construction, resulting without doubt in being the first of their kind built in Mexico, has been induced to contribute this discussion in order to bring out clearly the share of each. Mr. Pitkethly's apprehensions as to the adequacy of the system of ventilation adopted have not been realized, in part perhaps because the houses, though generally of only one story, have such high ceilings that the tops of their vent pipes are generally higher than the ventilating columns at the heads of the branch sewers.