Were it not for the fact (often somewhat embarrassing) that soil quite
incapable of making good pise will none the less produce enthusiastic
pise-builders, a warning as to the vital importance of the earth being
really suitable might seem superfluous.
The author has found some of the staunchest champions of pise-building
living on and valiantly struggling with stiff glutinous clay and almost
pure sand.
Even the most vigorous optimism can achieve little under such adverse
conditions unless soil-blending be resorted to, and even so,
pise-building begins to lose points in the matter of economy directly
complications of this sort are introduced.
Fortunately, however, England is well off in the matter of pise soils,
the red marls being amongst the very best.
A study of the country, or, failing that, of the geological maps, will
reveal a great tract of this earth extending diagonally right across
England, from Yorkshire down into Devonshire, where it ends
conspicuously in the beautiful red cliffs about Torquay.
There is a large area of the stuff in the Midlands, notably in
Warwickshire, with lesser patches here and there about the country.
Second only to the red marls come the brick earths, which, fortunately,
are also widely distributed.
"Brick earth" is merely clay that has been well weathered and
disintegrated under the action of wind, rain, frost, and organic agents,
the sulphides having become oxides, and what was a cold intractable
slithery mass having become merely a "strong" and binding earth.
It is probable that even stiff clay, if dug in the summer or autumn, and
left exposed for a winter, would prove sufficiently reformed to be quite
amenable for pise building in the spring.
After the marls and the brick earths there is an endless variety of
soils that will serve well for pise-building--some, of course, better
than others, but all, save the extremes (the excessively light and the
excessively clayey), capable of giving good results under proper
treatment.
Before putting pise construction actually in hand, however, the
intending builder will do well to submit samples of his earth to some
competent authority, that they may receive his blessing.
A fistful taken from a depth of 9 in., and another from say 2 ft. below
the surface, should give sufficient evidence as to the soil's
suitability or the reverse.