MU. K. SUTTON ON A WELL AT KIRUY BEDON. 
4U 
fiiul such a water in the lieart of the Chalk district is decidedly a 
novelty, and moreover they are just those things which are found 
least in the ordinary Norfolk waters. 
The origin of the iron and sulphuric acid is doubtless 
iron pyrites, ndiich consi.sts of about equal weights of iron 
and sulphur. This substance is known to exist occasionally 
in the clays and i^rls of this district, and is often found to 
be tlie i)etrifying aj^it of animal and vegetable remain.s. When 
tliis substance is exposed to the combined action of water and 
air, it is rapidly oxidized to sulphate of iron, commonly known 
as green copperas — a salt which is soluble in water. If this 
solution is in turn brought into contact with chalk, a double 
decomposition takes jdace, and the chalk, which is carbonate of 
lime, gives up its carbonic acid to the iron, and unites itself with 
the sulphuric acid, and thus we have sulphate of lime and carbonate 
of iron. That the iron does exist maitdy as carbonate in this water 
is evident from the fact, that the water is ([uite clear when first 
drawn, but soon begins to deposit on exposure to air or by boiling ; 
the explanation of this being, that free carbonic acid gas is largely 
present in the water, and keeps the iron dis.solved. When, on the 
other hand, this gas is driven off either by mere exposure or by 
boiling, the iron is no longer soluble, and falls down as a precipitate 
of red oxide. 
The ])resence, therefore, of the iron and sulphuric acid is 
accounted for ; but I must confess I am puzzled with respect to the 
magnesia. I can only imagine that there must be a boulder of 
dolomite or magnesian limestone in contact with the iron pyrites, 
or within the immediate neighbourhood. Or another hypothesis 
may be allowed, namely, that the well is sunk into an old sea-bed, 
the salts of Avhich are largely composed of magnesia, and from 
some protecting cause have not been n'ashed out of the soil by 
diiTusion among the surrounding ground-waters. This view is 
much favoured by the abnormal quantity of chlorine. 
If I may venture an opinion trenching somewhat on the domain 
of the geologist, I should say that this well has been sunk into a 
pocket, or fissure, surrounded by some impermeable, or at least not 
I easily permeable, material such as clay, in which these concentrated 
t chemical substances have been stored up for ages, but that the open- 
i ing of this well lu\s disturbed the strata, admitting air and water, 
VOI... IV. E 
