he
set; they should be of the same size, about eight inches being a
convenient diameter, and should be kept together in a warm place.
Three are filled with sand, seven with subsoil, and the remaining ten
with surface soil. Three of the subsoil pots are uncropped, two being
stored moist and one dry. Four pots of the surface soil are uncropped
and moist, a fifth and sixth are uncropped and dry, one of these
contains earthworms (p. 54). Four glazed pots, e.g. large jam or
marmalade jars, are also wanted (p. 69). Mustard, buckwheat, or rye
make good crops, but many others will do. Leguminous crops, however,
show certain abnormal characters, while turnips and cabbages are apt to
fail: none of these should be used. It is highly desirable that the
pots should be duplicated.

The plots also should be started in the school garden as early as
convenient. Eight are required for the set: their treatment is
described in Chap. IX. Plots two yards square suffice.

A supply of sand, of clay, and of lime will be wanted, but it is not
necessary to have fresh material for each lesson. The sand may be
obtained from a builder, a sand pit, the sea shore or from a dealer in
chemical apparatus. The clay may be obtained from a brick yard; it
gives most satisfactory results after it has 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 bra