"But you really have not," Adelaide replied. "I keep books for papa, and I am very much interested in these social and economic questions which are so fundamental to the perpetuity of our State and National prosperity. I have been both entertained and instructed by these discussions; and I might say, honored, too, that you do not consider me too young and foolish to talk of serious subjects."
"I am sure it is kind of you to make good excuses for me. You have at any rate relieved my mind of some burden, but I am sure you are the only woman I have ever known, except my mother, who could endure discussions of this sort. I have so greatly enjoyed the few short visits I have had with you. I wish I might write to you and I shall be so much interested to learn what success your father has if he begins a system of soil improvement. Would it be presuming to hope that I might hear from you also?"
"I am papa's stenographer," she replied, "and perhaps he will dictate and I will write. We will be glad to hear of your safe return,—and you,—you might ask papa. Now, I shall soon be out of sight."
"Please don't," begged Percy. "It is still forty-five minutes 'at least,' before the train comes. Let me go a piece with you. I will leave my suit case here and with nothing to carry I shall easily walk a mile in twenty minutes. May I drive, please?"
"No, I will drive. I want to ask you another question, and I am afraid you would drive too fast.
"You mentioned some long-continued scientific investigations which I assumed referred to the yield of crops. What were they?"
"I meant such investigations as those at Rothamsted and also those conducted at Pennsylvania State College. I have some of the exact data here in my note book.
"In 1848, Sir John Lawes and Sir Henry Gilbert began at Rothamsted, England, two four-year rotations. One was turnips, barley, fallow, and wheat; and the other was turnips, barley, clover, and wheat. Whenever the clover failed, which has been frequent, beans were substituted, in order that a legume crop should be grown every fourth year.
"The average of the last twenty years represents the average yields about fifty years from the beginning of this rotation.
"In the legume system, as an average of the last twenty years, the use of mineral plant food has increased the yield of turnips from less than one-half ton to more than twelve tons; increased the yield of barley from thirteen and seven-tenths bushels to twenty-two and two-tenths bushels; increased the yield of clover (when grown) from less than one-half ton to almost two tons; increased the yield of beans (when grown) from sixteen bushels to twenty-eight and three-tenths bushels; and increased the yield of wheat from twenty-four and three-tenths bushels to thirty-eight and four-tenths bushels per acre.