ckets are the quantities that suffice
when the teacher alone does the experiments, it not being convenient
for the scholars to do much.

{xv}

In conclusion the author desires to tender his best thanks to the Rev.
Cecil Grant of St George's School, and to Mr W. J. Ashby of the Wye
School, for having allowed him the use of their schools and appliances
during the progress of these lessons. Especially are his thanks due to
Mr Lionel Armstrong for much help ungrudgingly rendered in collecting
material, taking photographs, and supervising the experiments.

E. J. R.

HARPENDEN,
February, 1911.

{1}

CHAPTER I

WHAT IS THE SOIL MADE OF?

Apparatus required.

_Soil and subsoil from a hole dug in the garden. Clay. Six tripods
and bunsen burners or spirit lamps [2]. Six crucibles or tin lids and
pipe-clay triangles [2]. Twelve glass jars or gas cylinders [4]. Six
beakers [2] [1]._

If we talk to a farmer or a gardener about soils he will say that there
are several kinds of soil; clay soils, gravel soils, peat soils, chalk
soils, and so on, and we may discover this for ourselves if we make
some rambles in the country and take careful notice of the ground about
us, particularly if we can leave the road and walk on the footpaths
across the fields. When we find the ground very hard in dry weather
and very sticky in wet weather we may be sure we are on a clay soil,
and may expect to find brick yards or tile works somewhere near, where
the clay is used. If the soil is loose, drying quickly after rain, and
if it can be scattered about by the hand like sand on the sea shore, we
know we are on a sandy soil and can look for pits where builder's sand
is dug. But it may very likely happen that the soil is something in
between, and that neither sand pits nor {2} clay pits can be found; if
we ask what sort of soil this is we are told it is a loam. A gravel
soil will be known at once by its gravel pits, and a chalk soil by the
white chalk quarries and old lime kilns, while a peat soil is black,
sometimes marshy and nearly always spongey to tread on.

[Illustration: Fig. 1. Soil and subsoil in St George's school garden]

We want to learn something of the soil round about us, and we will
begin by digging a hole about three feet deep to see what we can
discover. At Harpenden this is what the scholars saw:--the top eight
inches of soil was dark in colour and easy to dig; the soil below was
reddish brown in