the
sugar, and even the smallest bit is sugar. It is just so with the rock
mass; but in the case of a chemical change you start with one thing and
end with another. You started with a big mass of rock which had in it a
portion that became changed by the acid acting on it. It ended in being
an entirely different thing which we call clay. So in the case of
chemical change a certain something is started with and in the end we
have an entirely different thing. The clay soils are often called mud
soils because of the amount of water used in their formation. The slate
that Myron brought for road making belongs to the clay family, and so
does shale.

"The third sort of soil which we farm people have to deal with is lime
soil. Remember we are thinking of soils from the farm point of view.
This soil of course ordinarily was formed from limestone. Just as soon
as one thing is mentioned about which we know nothing, another comes up
of which we are just as ignorant. And so a whole chain of questions
follows. Now you are probably saying within yourselves, how was
limestone first formed?

"At one time ages ago the lower animal and plant forms picked from the
water particles of lime. With the lime they formed skeletons or houses
about themselves as protection from larger animals. Coral is
representative of this class of skeleton-forming animal.

"As the animal died the skeleton remained. Great masses of this living
matter pressed all together, after ages, formed limestone. Some
limestones are still in such shape that the shelly formation is still
visible. Marble, another limestone, is somewhat crystalline in
character. Another well-known limestone is chalk. Perhaps you'd like to
know a way of always being able to tell limestone. I'll drop a little of
this acid on some lime. See how it bubbles and fizzles. Now Albert will
drop some on this chalk and on the marble, too. The same bubbling takes
place. So lime must be in these three structures. One does not have to
buy a special acid for this work, for even the household acids like
vinegar will cause the same result. Albert will prove this to you.

"Then these are the three types of soil with which the farmer has to
deal, and which we wish to understand. For one may learn to know his
garden soil by studying it, just as one learns a lesson by study.

"I believe the boys from their last winter's work feel fairly familiar
with soils, I have in these three tumblers the three types of soi