se sand, (2)
fine sand, (3) wet clay, (4) humus or leaf mould, (5) mixed soil or
loam; and let each put in grains of wheat, two inches deep.

Allow five other pupils to plant seeds of buckwheat, under similar
conditions. Treat all pots alike as to time of watering and quantity of
water used on each and give them all equal light and heat. Note which
come up first. Which are highest in one week, in two weeks, in four
weeks?

12. This study may be continued in the garden by planting one plot each
of corn, wheat, and buckwheat. Plots ten feet by twenty feet are large
enough. Observe the rate of development in the plots. Which seems to
mature most quickly? Which blossoms first? In what respect are the
leaves of these plants alike or unlike? How do the stems differ?

Examine the blossoming and seed formation. When the grains are ripe,
collect a hundred of the best looking and most compact heads of each
grain and also a hundred of the smallest heads of each. Dry, shell, and
store the two samples of each grain in separate bottles. These samples
are for planting the following spring.

13. To show the need of moisture in germination: Fill two flower-pots or
cans with dry sand; put seeds of sunflower in each, covering them an
inch deep. Put water in one pot and none in the other. Examine both pots
after two or three days.

14. To show that heat is needed for germination of seeds: Plant
sunflower seeds in two pots as above; place one in a warm room and the
other in a cold room or refrigerator; water both and observe result in
three days.

15. To show that air is necessary for germination: Fill a pint sealer
with hydrogen (the gas collected over water in the usual way, as shown
in any Chemistry text-book). Put a few sunflower seeds in a small sponge
or wrap them loosely in a piece of soft cloth. Keeping the mouth of the
jar which has been inverted over water and filled with hydrogen, under
the surface of the water, introduce the sponge containing the seeds, by
putting it under the water and pushing it up into the jar. Seal the jar
without letting the gas get out. Put some seeds in another jar in a wet
sponge and leave the jar uncovered. Compare results after several days.

Here is a second experiment to prove this. Boil some water in a beaker
in order to drive out all the air, put a few grains of rice in the
water, and then add enough oil to make a thin covering on the water.
This covering will prevent air from mixing with t