“As a rule we shake the soil with water for three minutes and then it takes twenty minutes to separate the water from the soil.  This gives us the plant food in solution and with the addition of more water the nitrates, phosphoric acid, and potash in the soil immediately dissolve sufficiently give us a nutrient solution of the same concentration as we had before.  Thus there is always sufficient plant food in the soil so long as there is any of the original stock.”

“That is surely quick work,” said Percy, “but I wonder if the corn plant might not get somewhat different results from the soil analysis which it makes.”

“How do you mean?”

“Did you ever plant a field of corn and then cultivate it and watch it grow with increasing rapidity, until along about the Fourth of July every leaf seemed to nod its appreciation and thanks as you stirred the soil; and to show its gratitude, too, by growing about five inches every twenty-four hours when the nights were warm?”

“No,” replied the Chemist, “I have never had any experience of that sort.  I am devoting my life to the more scientific investigations relating to the fundamental laws which underlie these soil fertility problems.”

“Well, I was only thinking,” Percy continued, “that you analyze a fraction of a pound of soil in a few minutes, while the corn plant analyzes about a ton of soil by a sort of continuous process, which covers twenty-four hours every day for about one hundred and twenty days, and it takes into account every change in temperature and moisture, the aeration with any variation produced by cultivation, and also the changes brought about by the nitrifying bacteria and all other agencies that promote the decomposition of the soil and the liberation of plant food, including the action upon the insoluble phosphates and other minerals of the carbonic acid exhaled by the roots of the corn plants, the nitric acid produced by the process of nitrification, and the various acids resulting from the decay of organic matter contained in the soil.”

“I am very familiar with the literature of the whole subject of soil fertility,” replied the Chemist, “and our theories are being accepted everywhere.  I have just returned from a lecture tour extending from Florida to Michigan, and our ideas and methods are being very generally adopted, not only in this country but also in Europe.”

“The Chief of the Bureau very kindly permitted me to look over the maps and reports relating to the soils of Maryland and Virginia,” said Percy, “but in this literature I found no data as to the amount of plant food contained in the various soil types that have been found in the surveys.  May I ask if the Bureau has made any analyses to ascertain the total amounts of the different essential plant food elements contained in these different soils?”

“No,” the Chemist replied, “a chemical analysis gives practically no information concerning the fertility of the soil.  We have made no ultimate analyses of soils, although we have used the same methods of analysis in a study of the partial composition of the soil separates, or particles of different grades, such as the sand, the silt, and the clay.”