f March, 
x ^6 Salt Industry of England . 
Until the discovery of rock salt, it was only supposed that 
brine springs were formed by the solution of rock salt. It 
is now known that water permeates from the surface, and 
that, until recently, all the brine springs came from the top 
of the rock salt, or as it is locally termed, the “ rock-head. 
In addition to this source of supply, brine is now obtained 
in large quantities in the neighbourhood of Northwich, from 
the old rock-salt mines, into which water from the surface, 
together with brine from the rock-head, finds an entrance. 
The weak solution coming in contact with the old pillars 
and the remainder of the rock salt that was left unworked, 
is formed into pure brine ; and the chambers being pierced 
where the brine is fully saturated, the pumping goes on 
without the separating barrier being dissolved. There are, 
therefore, two sets of modern brine pits in existence, those 
of the rock-head and those of the inundated old workings. 
The precautions necessary for securing the brine shafts 
are in many respedts, identical with what is required in the 
rock salt pits, and having been earlier in point of time, the 
necessities seem to have been met as they arose. It seems 
that in sinking to many of the springs the supply of brine, 
when cut into, was so copious that the sinkers had to escape 
for their lives, sometimes rising up the shaft amongst the 
brine without any opportunity being afforded of seeing what 
was underneath, which accounts for the lateness of the dis- 
covery of the rock salt. In these sinkings, when it is still 
unknown at what depth the brine is likely to be met with, 
there seems to be no entire remedy against these sudden 
entries of brine. But in the proved districts it is now 
observed that before reaching the top of the rock salt, where 
the rock-head brine flows, there is often a bed of hard marl- 
stone, called “ the flag,” and that for a few feet above it the 
marl is of a granular stature, called horsebeans. 
Therefore, when these indications are observed, and the 
brine is expected to be found at a high pressure, the prance 
is to case the shaft sides carefully down to the flag, to keep 
them secure, and prevent surface water from entering. I he 
flag is then either blown through with powder, or bored 
through with boring rods. One of the best methods of tap- 
ping the brine, when under pressure, is to sink the shaft 
nearly as deep as to where the brine is expefted, and then 
to case it with iron cylinders, having an iron bottom to the 
lowermost cylinder, with two holes in it to which pipes may 
be attached. From each of these two pipe holes a column 
of pipes, of about four inches in diameter, is eredled inside 
the cylinders, either to the top, or as high as the brine is 
