mud has settled pour off the bulk of the water; stir
up the mud with the rest of the water; transfer it to an evaporating
basin, and evaporate to dryness.

12. Does this dried mud consist of very tiny grains of sand or of some
material different from sand? Can you find out with a microscope?

13. If the mud consists of real clay and not of sand it should be
possible to burn it into brick. Moisten the dried mud again. Roll it
if you can into a round clay marble. Leave this to dry slowly for a
day. Then bake it either in a chemical laboratory furnace or in an
ordinary fire.

14. Return to the soil used in Question 10, from which only the fine
mud has been washed away. Pour more water on to it, shake it {130}
well, and pour off all the suspended matter without allowing it more
than 5 seconds to settle. Repeat the process. Collect and dry the
poured off material as before. What is the material this time, sand or
clay?

15. Wash the remaining portion of the soil in Question 14 clean from
all matter which does not settle promptly. Are there any pebbles left?
If so, how large are they, and of what kind of stone?

16. Take a fresh sample of the soil. Mix it with distilled water in a
flask. Boil the mixture. Allow it to settle. Filter. Divide the
filtrate into two portions. Evaporate both, the larger portion in an
evaporating basin over wire gauze, the smaller portion in a watch glass
heated by steam. Is any residue left after heating to dryness?

17. Take a fresh sample of soil. Spread it on a clean sand bath and
heat strongly with a Bunsen flame. Does any portion of the soil burn?
Is there any change in its appearance after heating?

18. To a fresh sample of soil add some hydrochloric acid. Is there any
effervescence? If so, what conclusions do you draw?

19. Make a solution of soil in distilled water, and filter as before.
Is this solution acid, alkaline or neutral? Are you quite certain of
your result? Did you test the distilled water with litmus paper? And
are you sure that your litmus does not contain excess of free acid or
free alkali?

Peat.

20. Examine different varieties of peat collected (see Question 2) and
describe the appearance of each.

21. Burn a fragment of each kind of peat on wire gauze. What do you
notice?

22. Boil some peat with distilled water and filter the solution. What
colour is it? Can you tell whether it is acid, neutral or alkaline?
Evaporate some of th