THE FARMER'S MAGAZINE. 



471 



THE EMPLOYMENT OF SEWAGE. 



BY CUTHBERT W. JOHNSON, ESQ., F.R.S. 



Much and often has been urged upon the im- 

 portance of utilizing sewage, but hitherto to little 

 public advantage. Succeeding generations of 

 Englishmen will have, indeed, cause to ridicule 

 the tardiness with which we, the enlightened deni- 

 zens of the nineteenth century, provided against 

 such losses. Future Macaulays will tell how copi- 

 ously we talked over the pestilential drains of our 

 huge cities ; how staunchly we opposed every plan 

 propounded for the removal of the foul streams 

 which poured into our rivers. Such historians may 

 very likely allude to these facts as one of the many 

 recorded instances of really wise persons acting in 

 bodies as if they were devoid of all reflection. It 

 may hereafter form an amusing page, when the 

 account is given of the stout denials with which 

 the asserted agricultural value of sewage was met 

 by the lovers of everything that is stationary. It 

 may be said in such a detail that, though the great 

 meads of Milan, Edinburgh, Clipstone, irrigated by 

 town sewage, had for many long years shown by 

 their enormous amount of grass that town sewage 

 is most valuable in one way, at least, for agricul- 

 tural purposes, yet that, in the year 1857, its im- 

 portance was denied, and all attempts to aid its 

 application in this way as stoutly opposed. There 

 has been recently, however, under the auspices 

 of Sir Benjamin Hall, a few slight appearances of 

 an earnest endeavour to attempt something in this 

 way as regards the sewage of London. Some 

 valuable and comprehensive reports have been 

 made by the Government engineers ; a commission 

 has been sent to Milan to examine and report upon 

 the sewage-irrigated meads of Northern Italy, and 

 a kind of an undefinable dream seems to be steal- 

 ing over the metropolitan commissioners that some- 

 thing for the useful employment of the sewage of 

 London ought to be attempted. 



It will be well if the numerous readers of this 

 magazine remember these things at the present 

 period. It should, indeed, be especially urged by 

 the landholders, upon those to whom the great 

 metropolitan trunk drainage plan is entrusted, the 

 importance of remembering the claims of agricul- 

 ture to the use of the sewage; that to promote 

 these objects the higher the level of the main 

 sewer, the greater will be the extent of land to 

 which its contents will flow by its own gravity. 

 Let such engineers also be made aware that the 

 further the stream of sewage flows from populous 



places, the more valuable it becomes as a fertilizer. 

 The same remark, in fact, applies to many other 

 manures : for instance, the same weight of town 

 dung which is worth twelve pence in London, is 

 worth twelve shillings fifty miles from the metro- 

 polis. In the one place the supply is greater than 

 the demand ; in the country the demand is greater 

 than the production. 



Then, again, it must not be forgotten that the 

 chief, the best use of sewage, is in the irrigation of 

 grass land. Now, in the immediate neighbourhood 

 of towns, the pastures are commonly either not 

 readily obtainable, or they are subject, when irri- 

 gated by impure water, to certain real or imaginary 

 sanitary objections. Odours are supposed to arise 

 — disease is suspected to be caused by their ema- 

 nations. Such obstacles do not arise in a thinly- 

 populated country. Let me instance the case of 

 the proposed course of the sewage of northern 

 London towards the sea. The marshes of Essex 

 here offer abundance of land suitable for sewage 

 irrigation. Take the course of the Thames, or 

 examine that of the little river Crouch, which 

 rises near Brentwood, and falls into the sea at 

 Burnham. On the banks of this stream there 

 is hardly a village to be met with : large marshes 

 here present themselves, tenanted only by live 

 stock. 



The clay soil, too, of these great pastures, is for- 

 tunately the best adapted to the purification of 

 liquids rich in organic matters. On this important 

 branch of the inquiry, the lately-published results 

 of Professor Voelcker's inquiries are well worthy 

 of our patient examination. They will repay us, 

 too, in other ways, if we study them carefully. 

 In these we may include the important questions 

 of Autumn manurings and the top-dressing of 

 pastures. The following trials of Mr. Voelcker 

 were made with the drainage from a rotten dung- 

 heap. He tells us {Jour. Roy.Ag. Soc, vol. xviii,, 

 p. 140) :— 



" The surface-soil employed in this trial contained 

 a good deal of organic matter, a fair proportion of 

 clay, little sand, and a moderate proportion of car- 

 bonate of lime in the form of small fragments of 

 iiir.Ci'.one. It was a stiflish soil, belonging to the 

 clay-marls. Its subsoil was richer in clay, and of 

 a more compact texture and less friable character 

 than the surface-soil. The mechanical analyses of 

 soil and subsoil gave the following results :— - 



S K 2 



