Lessons on Soil | Page 5

been ground ready for brick
making. Modelling clay is equally satisfactory. A supply of rain water
is desirable.

For a class of twelve children working in pairs at the experiments the
following apparatus is wanted for the whole course:--
{xiv}
Six tripods and bunsen burners or spirit lamps [2] twelve pipe-clay
triangles [4] twelve crucibles or tin lids [3] sixteen gas jars [4] twelve
beakers 250 c.c. capacity [4] two beakers 500 c.c. two beakers 100 c.c.
six egg-cups [2] twelve funnels [3] six funnel stands [1] six perforated
glass disks [3] two tubulated bottles 500 c.c., four corks to fit cork
borers 4 lbs. assorted glass tubing pestle and mortar twelve Erlenmeyer
flasks 50 c.c. [3] six saucers twelve flatbottomed flasks 100 c.c., six
fitted with India rubber stoppers bored with one hole [3], and six with
ordinary corks [3] box as in Fig. 13 six glass tubes 1/2" diameter, 18"
long [2] six lamp chimneys [3] six test tubes, corks to fit three
thermometers soil sampler (p. 88) balance and weights two retort
stands with rings and clamp.
The figures given in square brackets 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 colour and very hard to dig; one changed into the
other so quickly that it was easy to see where the top soil ended and the
bottom soil began; no further change could, however, be seen below the

eight inch line. A drawing was made to show these things, and is given
in Fig. 1. You may find something quite different: sand, chalk, or solid
rock may occur below the soil, but you should enter whatever you see
into your notebooks and make a drawing, like Fig. 1, to be kept for
future use. Before filling in the hole some of the dark coloured top soil,
and some of the lighter coloured soil lying below (which is called the
subsoil), {3} should be taken for further examination; the two samples
should be kept separate and not mixed.
First look carefully at the top soil and rub some of it between your
fingers. We found that our sample was wet and therefore