In a laboratory experiment, made at college it was shown that when
raw phosphate was shaken with water and then filtered, the filtrate
contained practically no dissolved phosphorus; but, if a dilute
solution of such salts as exist in kainit was used in place of pure
water, then the filtrate would contain very appreciable amounts of
phosphorus.

In addition to this benefit, the kainit will furnish some readily
available potassium, magnesium, and sulfur; and, by purchasing
kainit in carload lots, the potassium will cost us less than it
would in the form of the more expensive potassium chlorid or
potassium sulfate purchased in ton lots. Of course we do not need
this in order to add to our total stock of potassium, but more
especially I think to assist in liberating phosphorus from the raw
phosphate which is naturally contained in the soil and which we
shall also apply to the soil, unless the Government permits the
fertilizer trusts to get such complete control of our great natural
phosphate deposits that they make it impossible for farmers to
secure the fine-ground rock at a reasonable cost, which ought not, I
would say, to be more than one hundred per cent. net profit above
the expense of mining, grinding, and transportation. We may feel
safe upon the matter of transportation rates, for the railroads are
operated by men of large enough vision to see that the positive and
permanent maintenance of the fertility of the soil is the key to
their own continued prosperity, and some of them are already
beginning to understand that the supply of phosphorus is the master
key to the whole industrial structure of America; for, with a
failing supply of phosphorus, neither agriculture nor any dependent
industry can permanently prosper in this great country.