ON THE TREATMENT AND UTILIZATION OF SEWAGE. 67 



B, C, D, E, G, H, K, M, N, 0, P, and Q) is composed of a very loose open 

 sand and gravel overlying coarser sand and gravel in every case ; and in 

 many places it has been impossible, in the laying out of the land, to prevent 

 the yellow subsoil from being exposed. The accompanying analyses of the 

 soil taken from a part which had not been sewaged will show its extra- 

 ordinary poverty in organic matter ; and if this is taken into account, and if 

 it is also recollected that aU the crops were got into the ground during 

 the late almost unprecedented drought, and that from repeated workings and 

 shiftings the soil was in an abnormally dry condition, it will be seen at 

 once that it was necessary in every case to apply a much larger quantity per 

 acre of moisture and manure in the form of sewage for starting the first crops 

 than would ever be necessary under ordinary conditions of farming. More- 

 over, the tenant, while bound so to utilize the whole of the sewage of the 

 town of Eomford as to prevent the pollution of the river, has only a limited 

 area of land on which to apply it, and therefore he cannot avoid putting on 

 in many cases more sewage (that is, manure) than would otherwise be ne- 

 cessary ; but as such unusual conveniences exist on the farm for measuring, 

 not merely the sewage going on to the farm, but also the effluent water es- 

 caping, it wiU be quite possible to ascertain during the ensuing twelve months 

 exactly how much manure is placed upon the land, and very nearly with the 

 same exactness, how much is utilized, and how much wasted. However, as 

 absolute accuracy cannot be attained on so large a scale, and as the tenant 

 is bound, as before explained, to apply a certain quantity of sewage over the 

 whole area of the farm, whether his crops actually require it or not, he has 

 constructed some large wooden boxes of 2|-inch deal carefull}^ tongued and 

 grooved at the joints and strongly bolted together with iron bolts. These 

 boxes are 6 feet deep ; they are filled with earth carefully taken so as to 

 represent an average section of the farm, and the superficies of the earth in 

 each box (in other words, the inside measurement of each box) is equal to 

 •001 of an acre. The boxes are sunk in a huge ditch on the farm, which has 

 not yet been obliterated ; and they are so packed round as to reduce to a 

 minimum, quite inappreciable, the difference between their evaporation and 

 internal temperature and those on or below the natural surface of the ground. 

 The bottoms of the boxes have also been so constructed as to give a slight 

 drainage towards the centre, and also towards one end. In the centre of 

 each a small drain-pipe has been laid, and at the end of it a hole has been 

 bored in the end of the boxes so as to admit of the free exit of the effluent 

 water. These boxes, then, aff'ord the means of carrying out experiments with 

 accuracy, whUe they are yet upon a scale and under conditions which 

 make them accord strictly with actual practice. Such experiments have 

 never yet been conducted, and their value cannot be overrated, more espe- 

 cially as explanatory of the observations conducted as to the actual practice 

 on the farm itself ; for instance, it will be found that of the total amount of 

 the manurial constituents of the sewage applied to the farm a certain quan- 

 tity is wasted and escapes in the effluent water. The experiments in these 

 boxes wiU at once prove whether such escape is due to the application of a 

 quantity of manure in excess of the requirements of the plants and their 

 power of assimilating it, or whether the waste of a certain percentage of 

 maniire applied when in a state of solution by irrigation is a necessary defect 

 of the system ; that is to say, whether, when quantities of manure are applied 

 only sufficient for the chemical wants of the plants, it is nevertheless not in 

 the power of the plants and the soil and the other agents at work to isolate 

 that manure from the water in which it is dissolved, and to retain the whole 



r2 



