_Peat_ is also largely vegetable matter, consisting of tough roots,
partially decayed leaves, moss, etc. It is quite dense and compact and
in some regions is used for fuel.


HOW WERE SOILS MADE?

As a help in finding the answer to this question collect and examine a
number of the following or similar specimens:

_Brick._--Take pieces of brick and rub them together. A fine powder or
dust will be the result.

_Stones._--Rub together pieces of stone; the same result will follow,
except that the dust will be finer and will be produced with greater
difficulty because the stones are harder. Some stones will be found
which will grind others without being much affected themselves.

_Rock Salt or Cattle Salt._--This is a soft rock, easily broken. Place
on a slate or platter one or two pieces about the size of an egg or
the size of your fist. Slowly drop water on them till it runs down and
partly covers the slate, then set away till the water dries up. Fine
particles of salt will be found on the slate wherever the water ran
and dried. This is because the water dissolved some of the rock.

_Lime Stone._--This is harder. Crush two samples to a fine powder and
place one in water and the other in vinegar. Water has apparently no
effect on it, but small bubbles are seen to rise from the sample in
vinegar. The vinegar which is a weak acid is slowly dissolving the