ON DRAINING. 87 



sometimes in beds. It is intensely liaril, and interferes much 

 with Loth the economy and despatch of dig'ging- the drains. 

 It is the protoxide of iron of the chemists, and furnishes, by 

 its fine dissemination in the soil, the matter dissolved by 

 means of carbonic acid in. the water which enters the drains, 

 becoming' peroxide in the manner described by Mr. Phillips. 

 The term iron, or rust of iron, would convey to the mind 

 an idea that this ferruginous matter was heavy, and would 

 Cjuickly settle; but when it is considered that all substances 

 chemically dissolved in water and precipitated, are infinitely 

 fine, each atom is, in a practical sense, light, and easy of re- 

 moval ; and, in reality, this substance is seen to issue from 

 the mouths of drains in the form of light, flocculent, floating' 

 little masses, which settle Avhen the water is quiet, or are 

 easily brought to rest by stones, grasses, &c.; and this has 

 actually g-iven rise to a notion with some people, that it Avas 

 a vegetable substance, and grew in drains. 



Up to the present time, not a trace of this ferruginous 

 matter is to be discovered at the outfall of any one of the 

 pipe-drains laid at Drayton Manor; there is not even a 

 stain of its presence visible on the ends of any of those 

 pipes which discharge into open ditches, and where it might 

 be expected to exhibit itself; nor have I yet observed any 

 deposit of the substance in the ditches ; so that the result 

 is very encouraging. The time, however, has been too short 

 to permit us to indulge in absolute certainty as to their per- 

 manent action; yet I may mention one or two circumstances 

 as confirmatory of the fact that earthy matter does not enter 

 the pipes, and that therefore nothing has to be dealt with 

 hut the iron. There is no appearance of any sand or other 

 earthy bodies having accompanied the water of drainage, 

 which is brilliantly clear; and in one field where I had the 

 opportunity of continuing a line of pipes through the field 

 into a head of water which I could stop out, or allow to flow 

 through the drain 290 yards long, at will, no sand was 

 washed out by it, thus giving proof that none had entered 

 the drain with the water of drainage. I do not feel to be 

 thoroughly or sufficiently acquainted with the phenomena 

 attending this drainage, ibr although my previous confidence 

 in the non-transmission of earthy matter by the collared 

 pipes has been strengthened, as well as the expectation that 

 the flow of water in the confined channel would sweep out 

 any fine rust of iron which might be deposited therein, I do 

 not yet, hovv'ever, understand the absence of the appearance 



