583 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



"It will be found that after six tons of night soil and urine, diluted with 

 about forty tons of water, have been applied to an acre of land, in an hour 

 no offensive smell will be perceptible. 



"A large portion of the valuable properties that are lost from decompo- 

 sition and evaporation, by the retention of manure in the dry state, or in 

 its application as top-dressing, is saved by its being diluted and carried in 

 water under the surface of the soil, among the roots of plants." 



In the same paper plans and estimates for farm irrigation, by the use of 

 a steam engine, with a system of pipes, hydrants and hose, are given in 

 detail. 



The arguments in favor of sewage irrigation are forcible in themselves, 

 and confirmed by the lights of expeiience. A principle deduced from cor- 

 rect theories is often doubted and delayed in application, if such applica- 

 tion is novel in character; but experience adds force and conviction to 

 every theory, experimentally. The valuable character of sewage flow; the 

 deodorising effect of water which dilutes it; the superior processes of ap- 

 plicati(m to the roots and fibers of the vegetable kingdom, are not only 

 clear in the chemists' laboratory and the engineer's library, but are demon- 

 strated on a scale of most conclusive experimental testimony, which "he 

 who ruhs maj' read." 



The engineering question of irrigation by gravitation, as at Milan and 

 Edinburgh, is simple in its details of application. It may also be confi- 

 dently asserted that in those cities, with adjacent farming lands so located 

 as to be easily accessible from a central elevation, which will admit the 

 construction of a sewage reservoir and its supply by pumping power, the 

 resultant benefits will largely exceed the outlay for engine power, pipage, 

 and reservoirs; but in those cases, like New York, where vast quantities 

 of sewage flow must be discharged, at points far distant from cultivated 

 lands, and at tide level, the item of cost in transportation becomes formida- 

 ble, and cannot be overlooked. 



The conclusion under the head of utilization is that a due rog^ird to a 

 matter of public duty and profit requires the careful study of the local 

 characteristics of every city and town, in arranging its plans of sewage 

 flow, so as to make it available in all proper cases which admit the process 

 of irrigation, by gravitation or by pumping, within the limits of prudential 

 expenditure. In the case of Brooklyn, it is not improbable that the sew- 

 age flow into Gowanus bay might be elevated to the easterly ridge and 

 distributed over the Flatbush farms, in part, with valuable results. The 

 possibility justifies a careful examination, in this case, as in all others 

 which seem favorably located. Two important benefits are secured by this 

 process; the soil, depleted by its crops, receives back again its chief sources 

 of production, and yearly renews its vigor; and the vast flood of contami- 

 nation pouring from the intestine ducts of a densely populated town, is 

 deprived of its noxious eflfects on the riyers which must otherwise receive 

 its flow and the atmosphere, otherwise charged with its exhalations. 



The principles of arrangement, which .should govern an engineer in any 



general plan of sewerage, involve several important questions of practice. 



The ancients, in their magnificent public works, which include expensive 



drainage construction, as at Rome, Salopia, Genoa, Agrigentum, Hercula- 



