_Editor Popular Science Monthly_:
SIR: A correspondent, Mr. C. Wood Davis, of Peotone, Kansas, appears
to think it his duty to prove that we can not produce wheat enough in
this country to meet our own future demands, and apparently regards it
as a personal matter when any one contests this position. He also
thinks he has found a small error in long division in the last article
which you printed from me on this question which I can not find, but
which if found and corrected would have no influence on the general
argument.
He also rebukes me in a most earnest manner for the alleged misuse of
the chemical term "phosphate of potash," which crept into my article
in connection with the right use of the term "phosphate of lime," when
I referred to the mineral phosphates of Kentucky, Tennessee, and
Florida. Technically he is apparently right. There is no permanent
form or no natural mineral form of phosphate of potash which can be
removed from place to place. Yet my article was revised by an
experienced geologist, thoroughly familiar with the chemistry of the
soil, before I sent it to you, and he failed to correct this technical
error. My own knowledge of chemistry is very limited.
It might be inferred, as my irascible correspondent points out, from
the manner in which I have called attention to the deposits of mineral
phosphates in Kentucky and Tennessee, that I thought these deposits
would yield phosphates of lime and phosphates of potash each in a
separate movable form, which could not be a fact. Yet my critic will
doubtless admit that the soils of many parts of this country are
stocked with potash sufficient for a very long period.
Many years ago, when I began the study of the cotton plant and its
growth, under the leadership of the late Prof. William B. Rogers, I
made reference to the existence of the vast supplies of phosphate of
lime and potash, which are necessary to the growth of the cotton
plant, in the Southern soils. I derived my conception of their origin
in the lowlands and plateaus in marine formations from Professor
Rogers, and also from the works of Professor Shaler. One may also
impute the large amount of potash that is found in the valleys and
mountain lands to the disintegration of the gneiss and other rocks of
the Appalachian chain, which have never been washed out by glacial
action or by glacial streams. If any one has been misled by this
slight misuse of chemical terms it may be well to state that phosphate
of potash does not exist, and I am told that it can not exist, in a
separate removable form.
We have not as yet discovered any large deposit or mine like that of
Stassfurt, in Prussia, yielding potash in a commercial form in which
it can be widely distributed. We import annually thousands of tons of
potash from Stassfurt. This deposit was discovered, as I am informed,
by accident, and it may be hoped that a similar accident may occur in
this country. These mines were originally opened for the production of
salt. In boring for salt the product of a stratum above or below the
salt, I know not which, was brought up, which was thrown aside as
worthless until an inquisitive visiting chemist examined it and thus
discovered this great source of potash. We possess enormous beds of
salt, of soda, and of alkalies, scattered throughout the area of this
country, in connection with which it may be hoped that we may
hereafter discover a deposit of mineral potash, or of the mineral from
which potash may be derived cheaply and in large quantities.
These two exceptions which have been taken to my article have no real
connection with the substance of the argument, which stands
independently either of the undiscoverable error in long division or
of the technical fault in the use of the term "phosphate of potash."
Yours very truly,