and salt were added, then some potatoes and other vegetables, a
piece of butter and a few scraps of meat. 'Stone soup,' thus made,
was a very satisfactory soup. He said that in practically all of the
tests of raw phosphate conducted by the various State Experiment
Stations, manure has been used as a means of supplying organic
matter to liberate the phosphorus from the raw rock, but in such
large quantity as to be entirely impracticable for the average
farmer to use on his own fields; and his opinion was that the entire
benefit was due to the manure. He had a little booklet entitled
'Available or Unavailable Plant Food--Which?' published by the
National Fertilizer Association, and said I could get a copy by
addressing the Secretary at Nashville, Tennessee."

"Fortunately," said Percy, "this is not a question of opinion but
one of fact; and it has been discovered that the fertilizer agents
who are long on opinions and short on facts prefer to sell four tons
of complete fertilizer for $80, or even two tons of acid phosphate
for $30, rather than to sell one ton of raw phosphate, containing
the same amount of phosphorus, for $7.50. In the manufacture of
acidulated fertilizers, one ton of raw phosphate, containing about
two hundred and fifty pounds of the element phosphorus, is mixed
with one ton of sulfuric acid to make two tons of acid phosphate;
and, as a rule, these two tons of acid phosphate are mixed with two
tons of filler to make four tons of complete fertilizer. A favorite
filler is dried peat, which is taken from some of the peat bogs, as
at Manito, Illinois, and shipped in train loads to the fertilizer
factories. The peat is not considered worth hauling onto the land in
Illinois, even where the farmers can get it for nothing; but it
contains some organic nitrogen, and, by the addition of a little
potassium salt, the agent is enabled to call the product a