the sewer and to demand the removal of the obstructing material; while in systems with large pipes, there is ample room for the accumulation of an offensive and dangerous amount of organic deposit with ample water way above or around it. Such sewers may go for a long time without cleaning, simply because they will perform their main office of carrying away sewage without being cleaned. (c) The ventilation of the system is much more complete than it would be possible to secure with the use of the larger pipes of the combined system. (d) There is no opening between the sewers and the surface of the street through which offensive odors can escape to the annoyance of the people, nor are there the filthy and objectionable catch basins by which it is attempted, not always successfully, to hold back street dirt, and which often become very offensive by decomposition during the intervals between These serious drawbacks are entirely eliminated. storms. In most towns of moderate size there is no occasion for the universal removal of surface water through underground channels. It is often, and indeed generally, necessary to carry street wash from points where it accumulates to a dangerous or inconvenient extent. Channels for this purpose may either be independent, shallow, and often short lines, leading to a near point of outfall; or, if the outfall of the foul system is sufficiently near at hand, its main sewer may, from the desired point, be sufficiently increased in size to take the surface water as well. Whether or not, and to what extent, this should be done, is a question, the decision of which calls for the judgment and experience of a competent engineer. KEENE. A movement was made for the sewage of Keene about 1876, when it was proposed to construct a combined system of sewers, varying in size from pipes twelve inches in diameter to brick sewers forty inches wide and sixty inches high. The cost of this work would have been so large that nothing was done toward its execution. The question was taken up again after 1880, when the success of the work at Memphis |