"Like the man that was too lazy to stop work when he had once
begun," remarked Mr. Thornton.

"Yes," said Percy, "but it is true that some of the States have
adopted the practice of reporting analyses of soils and fertilizers
on the basis of nitrogen instead of ammonia; and in the Corn Belt
States, phosphorus and potassium are the terms used to a large
extent instead of 'phosphoric acid,' and potash. The agricultural
press is greatly assisting in bringing about the adoption of the
simpler system, and the laws of some States now require that the
percentages of the actual plant food elements, as nitrogen,
phosphorus, and potassium, shall be guaranteed in fertilizers
offered for sale. It is one of those questions that are never
settled until they are settled right; and it is only a question of
time until the simple element basis will be used throughout the
United States, or at least in the Central and Western States."

"The so-called 'phosphoric acid' of the fertilizer agent is a
compound whose molecule contains two atoms of phosphorus and five
atoms of oxygen; and, since the atomic weight of phosphorus is
thirty-one and that of oxygen sixteen, this compound contains
sixty-two parts of phosphorus and eighty parts of oxygen. In other
words, this phosphoric acid, falsely so-called, contains a trifle
less than forty-four per cent. of the actual element phosphorus."

"Is the bone phosphate of lime that the agents talk about the same
as the 'phosphoric acid'?" asked Mr. Thornton.

"No, by 'bone phosphate of lime,' which is often abbreviated B. P.