In the instances we have referred to, the water passed through the first eight miles of the aqueduct, to a waste weir at Sing Sing, where it was discharged in six hours. This strengthens the opinion, that it will certainly pass through the whole line, as fast as at the rate of one mile per hour, which is the rate calculated on. The frequent use of the thermometer has shown that the temperature of the aqueduct was fifty degrees, in our coldest days previous to the 1st of January. This proves that neither the water nor the masonry of the arch will be exposed to frost. The variation of temperature between summer and winter is found to be only five degrees. We have only excavated the rock and earth between the two reservoirs of a width sufficient for two, instead of three lines of large pipes, which will furnish a sufficient supply for at least half a century. The saving in this particular amounts to 10,000 dollars. We were not able to make any arrangement with the contractors for the receiving reservoir at Yorkville, by which we could abandon, for the present, the construction of the northern division of this work, as proposed by us, with any advantage to the public so ;

much work having been already executed, and so much of the earth being required for the embankments of the streets surrounding the reservoir and the southern division, that we were obliged to let this reservoir proceed, as contemplated by our predecessors except, ;