262 
On Draining. 
" The large amount of peroxide of iron shown in the above ana- 
lysis, appears to me to be in consequence of the iron existing 
originally in a lower state of oxidation, in which state it has been 
dissolved by carbonic acid, and formed by the decay of organic 
matter in the soil, and then carried away by the drainage water ; 
when by subsequent exposure to atmospheric air it has been con- 
verted into insoluble peroxide. The other ingredients in the 
deposit would appear to have been carried down mechanically, in 
consequence of their existing in a very minute state of division.'' 
It thus appeared from the analysis that only 27 "8 per cent, of 
the deposit consisted of iron, and that the remainder, nearly three- 
fourths of the whole, consisted of foreign matter. This analysis 
powerfully fortified my hopes that the drains I was making might 
remain permanently open, if their mechanical structure were such 
as to admit water only, and no other earthy matters than such as 
might be chemically dissolved, in which case it was apparent that 
I should reduce the enemy to be contended with by nearly three- 
fourths of his strength, and direct against him, for expulsion, a 
more concentrated stream of water, by reason of the smaller 
dimensions of the conduit. Between November last and the 
present time some miles of drains have been executed in the soils 
referred to, abounding with bog-iron ore, locally called " pox- 
stone," the same as I have met with in North Devon under the 
name of " black-ram," and in Somerset under the title of " iron- 
mould." In other parts it is called by its proper name. It occurs 
in masses, both large and small, sometimes in beds. It is intensely 
hard, and interferes much with both the economy and despatch 
of digging the drains. It is the protoxide of iron of the chemists, 
and furnishes by its fine dissemination in the soil the matter dis- 
solved by means of carbonic acid in the water which enters the 
drains, becoming peroxide in the manner described by Mr. Phil- 
lips. The term iron, or rust of iron, would convey to the mind 
an idea that this ferruginous matter was heavy, and would quickly 
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 removal ; 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 when 
the water is quiet, or are easily brought to rest by stones, grasses, 
&c. ; and this has actually given rise to a notion with some people, 
that it was 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 tlie ends of any of those pipes which discharge into open ditches, 
and where it might be expected to exhibit itself; nor have I yet 
