1870.] of Sewage Irrigation. 27 



4. Total Submersion. — The method of carrying out this system 

 is by raising a bank round the field to be irrigated, and then turn- 

 ing the water into it, where it is left until absorbed or evaporated, 

 being from time to time replenished as may be necessary. It is 

 extensively carried out in Piedmont and Lombardy in the cultiva- 

 tion of rice, and, unlike any other, it is the only system of irrigation 

 that is considered likely to aifect the health of the inhabitants in 

 the immediate neighbourhood of its operation, its special drawback 

 being that it converts every field where it is practised into a swamp 

 of the worst possible description. 



In conclusion, we may give the following short particulars re- 

 garding the selection of crops to be cultivated by sewage ; on this 

 point, however, more experience is required, as, owing to the greater 

 facility by which it can be applied to grass, but few experiments 

 have been made for its use with other crops. Fast growing, succu- 

 lent grasses appear to be the favourite crops, and especially Italian 

 rye-grass, of which crops varying from 30 to 50 tons to the acre 

 may be obtained annually ; and on one occasion as much as 61 tons 

 were obtained in the year at the Lodge Farm, Barking. At Rugby 

 some experiments have been made in the growth of oats, and the 

 results reported to be of a most satisfactory nature. At Barking 

 a couple of roods of land were ploughed up, irrigated with sewage, 

 and sown with wheat; whilst a similar quantity of land, not 

 irrigated, was also sown. The yield of the sewaged land was 

 exactly 1-J time that of the land which was not so treated. Mangold 

 wurzel has been grown with excellent results at Chelmsford, and at 

 Barking the average return has been 50 tons per acre, just double 

 that grown upon unsewaged soil. Winter greens, lucerne, beet, 

 flax, celery, and cabbages have all been grown upon the farm at 

 Barking, and have produced returns beyond all expectation, the 

 onion being the only plant that evinced any repugnance at being 

 treated with sewage. 



Experience has now shown us that town sewage is not a 

 refuse, and that allowing it to fall into the nearest rivers, or into 

 the sea, is nothing more nor less than wilful waste, to such an 

 extent as to amount to a national loss, to say nothing of the con- 

 sequent diminution of food which ensues by the destruction of fish. 

 Few towns are so situated as not to be able to dispose of a portion, 

 at least, if not the whole of their sewage upon adjoining lands, and 

 where this is the case no more economical plan for getting rid of 

 it has yet been devised. Where such accommodation is wanting 

 it may be found necessary to have recourse to some one or other of 

 the artificial means of deodorization to which we have already 

 referred ; for although attempts to extract, by this means, a really 

 valuable solid manure have hitherto proved unsuccessful, it would 

 be unreasonable to draw the conclusion that means will not, sooner 



