little or no good. He wanted to use enough to change the general
character of the land--to make the light land firmer and the heavy land
lighter.

While I was with Mr. Lawes and Dr. Gilbert at Rothamsted, I went home on
a visit. My father had a four-horse team drawing lime every day, and
putting it in large heaps in the field to slake, before spreading it on
the land for wheat.

"I do not believe it pays you to draw so much lime," said I, with the
confidence which a young man who has learned a little of agricultural
chemistry, is apt to feel in his newly acquired knowledge.

"Perhaps not," said my father, "but we have got to do something for the
land, or the crops will be poor, and poor crops do not pay these times.
What would you use instead of lime?" --"Lime is not a manure, strictly
speaking," said I; "a bushel to the acre would furnish all the lime the
crops require, even if there was not an abundant supply already in the
soil. If you mix lime with guano, it sets free the ammonia; and when you
mix lime with the soil it probably decomposes some compounds containing
ammonia or the elements of ammonia, and thus furnishes a supply of
ammonia for the plants. I think it would be cheaper to buy ammonia in
the shape of Peruvian guano."

After dinner, my father asked me to take a walk over the farm. We came
to a field of barley. Standing at one end of the field, about the
middle, he asked me if I could see any difference in the crop. "Oh,
yes," I replied, "the barley on the right-hand is far better than on the
left hand. The straw is stiffer and brighter, and the heads larger and
heavier. I should think the right half of the field will be ten bushels
per acre better than the other."

"So I think," he said, "and now can you tell me why?" --"Probably you
manured one half the field for turnips, and not the other half." --"No."
--"You may have drawn off the turnips from half the field, and fed them
off by sheep on the other half." --"No, both sides were treated
precisely alike." --I gave it up --"Well," said he, "this half the field
on the right-hand was limed, thirty years ago, and that is the only
reason I know for the difference. And now you need not tell me that
lime does not pay."

I can well understand how this might happen. The system of rotation
adopted was, 1st clover, 2d wheat, 3d turnips, 4th barley, seeded with
clover.

Now, you put on, say 150 bushels of lime for wheat. After the wheat the
land is manured