is heating make a shallow notch in the glass with the wet corner of a
file in the direction you wish to make the cut. When the rod is hot
lay the end of it lengthwise on the notch. Very soon a little crack
will be seen to start from the notch. Lead this crack around the
bottle with the hot rod and the bottom of the bottle will drop off.)
(Fig. 23.) Make a rack to hold them. Tie a piece of cheese cloth or
other thin cloth over the small ends of the chimneys. Then fill them
nearly full respectively, of dry, sifted, coarse sand, clay, humus
soil, and garden soil. Place them in the rack; place under them a pan
or dish. Pour water in the upper ends of the tubes until it soaks
through and drips from the lower end (Fig. 22). Ordinary sunburner
lamp chimneys may be used for the experiment by tying the cloth over
the tops; then invert them, fill them with soil and set in plates or
pans. The sand will take the water in and let it run through quickly;
the clay is very slow to take it in and let it run through; the humus
soil takes the water in quite readily. Repeat the experiment with one
of the soils, packing the soil tightly in one tube and leaving it
loose in another. The water will be found to penetrate the loose soil
more rapidly than the packed soil. We see then that the power of the
soil to take in rainfall depends on its texture or the size and
compactness of the particles.

If the soil of our farm is largely clay, what happens to the rain that
falls on it? The clay takes the water in so slowly that most of it
runs off and is lost. Very likely it carries with it some of the
surface soil which it has soaked and loosened, and thus leaves the
farm washed and gullied.

What can we do for our clay soils to help them to absorb the rain more
rapidly? For immediate results we can plow them and keep them loose