On Draining. 
263 
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 permanent 
action ; yet I may mention one or two circumstances as confirma- 
tory of the fact that earthy matter does not enter the pipes, and that 
therefore nothing has to be dealt with but the iron. There is no 
appearance of any sand or other earthy bodies having accompanied 
the water of drainage, w hich 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, for although 
my previous confidence in the non-transmission of earthy matter 
by the collared pipes has been strengthened, as well as the expecta- 
tion 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, however, understand the absence of the appearance of iron 
deposit at the outfalls of these drains. Time and observation, 
assisted by an analysis of the issuing waters, which has already 
been commenced, and the drawing the attention of chemists gene- 
rally to the subject, may, I hope, by enabling us to detect causes, 
teach us how to improve effects. The subsoil generally in Drayton 
Manor Park consists of gravel internaxed with fine and very heavy 
sand alternating with, or broken in places by, a marly clay very re- 
tentive of water. It contained much water, our test holes standing 
full in the winter, or within 18 inches of the surface throughout. 
It was chiefly by the pickaxe that the trenches had to be opened, 
spades being of little use in the gravels. The sides fell in and closed 
so much that it was difficult, and, in some parts impossible, to keep 
an entire line of drain open before the pipes were obliged to be 
laid , so that the worst parts had to be done by instalments, the 
pipes being laid and covered up as the work proceeded — for, if not 
so done, the spewing sand was forced up from the bottom and 
through the sides by the pressure of water. All was secure, how- 
ever, when the collared pipes were laid and covered in. One 
drain, about 105 yards long, was laid in a quicksand, by using 
inch pipes completely sheathed in another larger pipe, and no 
packing or cover was employed. This drain, which is about 
6 feet deep, has never exhibited, at its outfall, a grain of sand ; 
the water is beautifully pellucid, and has maintained a discharge 
varying, however, with rain or drought, of about two gallons per 
minute. I conceive this method of sheathing pipes to be capable 
of forming a permanent drain through any species of quicksand 
or loose soil ; packing may be a useful and even necessary adjunct 
