"But you have not made analyses for total plant food in the soils or
conducted actual field experiments with crops grown to maturity?"
asked Percy.

"No, we have not done that," answered the Chief. "Those are old
methods of investigation which have been tried for many years and
yet no chemist can tell in advance what will be the effect of a
given fertilizer upon a given crop on a given soil."

"That is true," said Percy, "but neither can any merchant tell in
advance just what effect will be produced on the next day's business
by the addition of a given number of a given kind of shoes to a
given stock on his shelves. There are many factors involved in both
cases."

"Yes, you are right in that," said the Chief, "we are just beginning
to understand the chemistry of the soil, and we hope soon to have
very complete proof of the advanced ideas we already have concerning
the causes of the fertility and infertility of soils."

"Referring to the specific case of the Leonardtown loam of
Maryland," said Percy, "I find the following statement on page 33 of
the Report of the Field Operations of the Bureau of Soils for 1900.
After describing the Norfolk loam of St. Mary County, the writer
says:

"'The Leonardtown loam is a very much heavier type of soil. It
covers about forty-one per cent. of St. Mary County. The soil is a
yellow silty soil, resembling loess in texture, underlaid by a clay