SEWAGE. 



629 



eight years, in which he held the office of su- 

 perintendent of a Sabbath-school, he was ab- 

 sent from his post but twelve Sabbaths. 



SEWAGE, USE OF TOWN. The various ex- 

 periments conducted by the Metropolis Sewage 

 Company, London, both at Barking Creek and 

 on their experimental farm a little beyond 

 Barking, as well as those conducted by myself, 

 states Mr. Wm. Hope before the Institution of 

 Surveyors, on a smaller scale on my own land, 

 have given me an opportunity of acquiring 

 knowledge in this particular branch of agricul- 

 ture, which, I believe I may safely say, no one 

 else has enjoyed; and it is only the considera- 

 tion of these exceptional advantages which has 

 made me presume so far as to address the In- 

 stitution of Surveyors on such a subject. 



In considering the utilization of sewage by 

 irrigation, we may usefully divide it into three 

 heads: first, conveyance of the sewage from 

 the town to the country ; secondly, distribution 

 throughout the district proposed to be irrigated ; 

 thirdly, application of the sewage to the actual 

 soil or crops. 



Now, with regard to the first question I need 

 say very little. An experienced surveyor will 

 naturally avail himself of the readiest means at 

 his command for conveying a large body of 

 noxious liquid from one district to another. He 

 will be guided by local circumstances and local 

 materials in designing his work, and the nature 

 of the work will, in some degree of course, also 

 depend upon whether the levels of the ground 

 permit of gravitation either by purely natural 

 fall, or by means of a short lift, or necessitate 

 forcing by expensive machinery. I will merely 

 remark that there is of course a great conven- 

 ience for distribution in what I may term the 

 luxury of pressure. If the main culvert or 

 sewer be an iron pipe of any description, 

 through which the sewage is forced by power- 

 ful engines, it becomes a very easy and simple 

 matter to attach a pipe at any point for supply- 

 ing any land, no matter where situated ; but, if 

 the main outfall conveys the sewage by gravi- 

 tation only, then the sewage can only be distrib- 

 uted by the same means, and, of course, can 

 only be taken to land on a lower level than the 

 outfall, and this, in many places, becomes a 

 most serious difficulty. 



The distribution of the sewage of a small 

 town of 10,000 or 20,000 inhabitants is a simple 

 enough affair, for it is distributed on one farm 

 only, and that farm is, of course, chosen so as 

 to be more or less in a ring fence ; but, if it is 

 desired to deal with the sewage of a great city, 

 much more contriving is necessary. For short 

 distances and low pressures, earthenware pipes 

 may sometimes be used for the lateral channels, 

 but they are not satisfactory ; and it must al- 

 ways be recollected that the bursting or leakage 

 of a sewage-pipe is a somewhat serious affair, 

 even in the country. Iron pipes are, of course, 

 always the handiest and neatest things to deal 

 with, but they are expensive. Earth ditches 

 are perfectly effectual, and are, perhaps, the 



most convenient of all for communicating with 

 other minor branches ; but, unless the lay of the 

 land coincides exactly with the fall required to 

 be given to distributing channels, the earth 

 ditches soon become very expensive in con- 

 struction, and wasteful in the space occupied. 

 And, in view of the several difficulties and 

 drawbacks attending the use of either ditches, 

 or earthenware or iron pipes, I have devised a 

 new method of distributing sewage, which, I 

 think, is likely to prove useful in some localities. 

 It is very simple consisting merely of sheet- 

 iron troughs, with a semicircular section, 

 supported upon rough wooden legs of any re- 

 quired size and length. Such iron troughs, at 

 whatever elevation from the ground and in 

 most cases a very few feet are quite sufficient 

 occupy no more space than a ditch would 

 occupy when running with a fall coincident 

 with that of the land itself. Therefore, there 

 is no permanent waste of land in a broad em- 

 bankment, and the outlay becomes less than 

 the outlay in constructing a raised-up ditch 

 when a very few inches in height are attained. 

 If any unusual height is necessary, to bridge 

 over a hollow for instance, the section of the 

 trough may be slightly altered, and, instead of 

 being semicircular, the diameter may be dimin- 

 ished, and to the prolongation of the sides of 

 the smaller semicircular trough, thus formed, 

 may be riveted stronger plates to act as girders, 

 and so the original sectional area would be 

 preserved. With troughs so constructed, hav- 

 ing a few angle-irons bent all round them 

 outside, a very strong and durable kind of 

 semitubular bridge would be obtained. I may 

 mention that I have made an experiment with 

 about a mile and a half of semicircular trough- 

 ing far thinner than that which would be used 

 in a permanent work, and that this troughing 

 is placed at an unusual height, being for a great 

 part of its length from 16 feet to 22 feet above 

 the ground. It is, moreover, in a most exposed 

 situation, and has, nevertheless, stood all the 

 severe gales of last winter without the very 

 smallest sign of giving way. 



Difficulties for the first few years may arise 

 in arranging for the distribution of the Avhole 

 sewage of a large town over a wide area of 

 land, if there are a few obstructive people in 

 the area who fancy that they could make more 

 by standing out and refusing to take the sew- 

 age, than by taking it, if compulsory powers 

 have not been obtained. But, even in this case, 

 it would be a pecuniary rather than a physical 

 difficulty. There need, therefore, be no greater 

 difficulty in designing the different channels by 

 which the sewage of a large town may be distrib- 

 uted to any given number of farms, than there is 

 in an analogous kind of work which has been 

 executed by very many gentlemen now present, 

 namely, draining several separate estates into 

 one common outfall. It is simply inverting the 

 process, and, instead of collecting the water 

 from the various estates into one main channel 

 by which it would run aw^y, bringing the water 



