s of packing though no water can be squeezed from it. In
its best condition, the water of the soil adheres as a film of moisture
about every particle. Free water is to be avoided since it excludes the
air from the soil.

6. Equal weights of soils of different kinds and degrees of fineness are
placed in funnels or in inverted bottles with bottoms removed. Water is
then slowly added to each until it begins to drop from the lower end.
From this is seen (1) the great value of humus as a water holder, (2)
the advantage of fine soil over coarse. For retention of water by
absorption, consult _Nature Study and Life_, Hodge, page 382.

7. Take two wooden boxes (chalk boxes will do), fill one box with moist
sand and the other with moist leaf-mould. Weigh the boxes separately and
leave them for three or four days in a warm room. Weigh again and note
decrease from evaporation. The sand dries out much faster than the
humus. Test with clay, gravel, and loam, also with mixtures of these and
leaf-mould.

8. Take three paint cans; punch holes in the bottoms. Fill each with
good soil well shaken down. Stand the cans in water till the tops are
moist, then place them in a warm, dry place. Loosen the soil on the top
of No. 1 to a depth of one inch; on No. 2 to a depth of two inches;
leave No. 3 untouched. Find out after a few days which is drying out
fastest. How may soil be treated so as to lessen evaporation of water?

DRAINAGE

9. Gravel and sand allow water to run away rapidly, but where the soil
is fine or closely packed as in clay soils, under-drains are necessary
(1) to carry off the surplus water, (2) to allow air to enter the soil,
(3) to warm the soil (wet soil is colder than dry).

Take two equal-sized tin cans, make several holes in the bottom of one,
place therein a layer of broken pottery or stones, and fill with good
soil. Fill the other with similar soil but make no holes for drainage.
Plant in each can a healthy plant of the same size and kind. Water both
till the soil is saturated and continue watering every two or three
days for six weeks. Note (1) the progress of the plants, (2) the
temperature of the soils, (3) which plant has the largest and deepest
roots. (See _Bulletin 174_, Ontario Department of Agriculture.)

10. Take five equal-sized boxes, provide for drainage, and fill No. 1
with wood, earth, or humus, No. 2 with clay, No. 3 with sand, No. 4 with
a mixture of clay and humus, No. 5 with a mixture of sand a