The report of the council committee on sewerage, found on another page of this paper, is a wellwritten paper. lts one weak spot can very quickly be pointed out. L. E. Cooley, chief engineer of the sanitary district of Chicago, and a very competent authority, makes an estímate from the data of Swift's mili having 50 feet horse power with 11 feet head and the Superior milis seventy-five horse power with 16 fee head, that the water would carry of the sewerage of a population o 16,000. Evidently Mr. Cooley was not informed that on Sunday Swift's mili is closed down and on many other occasions during the dry season, during which the water is collected in the dam. On such occasions the water which wouk carry off the sewerage for only 16, ooo people when aliowed to pass through the race, would be clearly inadequate. Then again, the bed of the Huron river is wide enough for a river of ten times its size. The wider the bed of the river, the less depth of water and the less capacity for carrying off the large quantities of sewerage, for as Prof. Greene in his repon says, "the transporting power of water depends on its depth as well as its velocity." In dry weather there are places below the city where one can cross the river almost without wetting their feet. In this connection Prof. Greene's argument against a large sewer to take up the bed of Allen creek is worth reading; "The tributary sewage would make a trickling stream on the comparatively flat bottom of the large sewer, checked in its velocity by the ronghness of the bricks; deposits would accumulate by reason of the sluggishness of the flow, and decomposition would set in and continue until a shower of rain should flush the sewer." This is the argument against using the Huron. The water is shallow. Stones rise above the surface in all directions and in many places the river is filled from bank to bank with weeds and grasses, which grow higher than the water. This certainly would retard the sewage. These are factors evidently not taken into consideration in the computations, and destroy the entire value of them. For, if the premises are wrong, the entire-argument is invalid.