This I do not consider an objection, as I am fully satisfied, iron pipes will make the most suitable conduit for the water on such a bridge, and therefore have had a plan prepared, with a view to comply with the law, arid avail of the economy and greater permanence from a less elevated structure. Owing to the less height required for the arches, and by adopting iron pipes for the conduit, the top of the parapets will be 114 feet above high water mark, which is 17 feet lower than the original plan. The superstructure being lighter than necessary for an aqueduct of masonry, a diminished thickness of arch stone may with equal safety be adopted. The plan of piers and arches, also the hydraulic foundations, and manner of constructing coffer dams, and the character of the masonry in general, are proposed to be similar to that designed for the original plan. Some modifications in the construction and securing of the coffer dams, will be provided for in the estimates. For greater security, the expense of the coffer dams will be increased, by a more extensive excavation of the mud than was originally contemplated, and a course of plank to be put on the same before sinking. This plan, it will be perceived, has, in its general appearance, a great degree of similarity to what has, for distinction, been called the high bridge. It

will, however, in consequence of its being of less height, and adapted to support a lighter superstructure, be less expensive. In the first instance, it is proposed to put down two three-feet pipes, which will probably be sufficient to supply the city for at least fifty years ; but to adapt the work to receive two four-feet pipe, which will be sufficient when the full