310 NATURAL HISTORY OF THE FARM 
Where burrowing crawfishes abound, their holes will be 
found—some of them capped over with mud chimneys since 
the drought began. We can test the depth to which the 
water-level in the soil has descended by probing the craw- 
fish holes with a stick. 
Where we lose the channel of the brook, 
as we pass out into a small grassy flood-plain, 
we find that though there is no water in sight, 
there is moisture in the soil. Such soil-gather- 
ing things as the fowl-meadow-grass (fig. 135) 
are making the most of the situation; they are 
covering the plain with a tangle of stems that 
will strain out of subsequent floods their burden 
of silt and trash. Thus will the plain be built 
a little higher; another layer will be added to 
form rich moisture-holding soil. 
By the side of the brook gone dry, nature 
sets us examples in the conservation of 
moisture. There we may find plants burned 
to death with the drouth; others of the same 
species wilted sadly, but still alive; and others, 
green and flourishing. The differences are 
mainly due to the disposition of the soil about 
Fic. 136. ides; their roots; soil hard and bare in the first case, 
i aed and well adapted to facilitate loss of water; 
and loose soil well covered from the sun in 
the last case, and full of reserve moisture. 
Somewhere, along our brook, we may come upon a reedy 
swale now dry enough to walk across, but never dry enough 
for field-crops, and therefore left unmolested by the plow. 
It is apt to be filled with sedges and marsh ferns, with a 
few cat-tails in the wettest spots, and to have round about, 
a fringe of moisture-loving composites such as boneset, joe- 
pye weed, swamp-milkweed, goldenrod and New England 
