ears since has the Thomas-slag been recognized as an eminently
fit manure for certain soils. The manufacturers, however, who grind the
Thomas-slag into flour and carry it to market, have built a ring, and,
to the injury of the farming interests who make bitter complaints on
that score, they keep the prices high. Thus every progress is crippled
by greed in bourgeois society. Another and at present inexhaustable
source of fertilizers is offered by the deposits of potash in the
province of Saxony and contiguous regions. The Prussian State owns a
number of potash works and it also made the attempt to monopolize the
industry, to the end of raising the largest possible revenues for the
Treasury.

If the opinion of Julius Hensel on the subject of fertilizers proves
correct, it will mean a revolution in the theory of fertilization, and a
complete saving of the expenses now made for the importation of
fertilizers, amounting for guano and Chile saltpeter to from 80 to 100
million marks a year.[202] Hensel makes the emphatic claim, and produces
numerous proofs of the correctness of his views, that the mineral of our
mountains contain an inexhaustible supply of the best fertilizing
stuffs. Granite, porphyry, basalt, broken and ground up, spread upon the
fields or vineyards and furnished with a sufficiency of water, furnished
a fertilizer that excelled all others, even animal and human
refuse.[203] These minerals, he claims, contain all the elements for the
cultivation of plants: potash, chalk, magnesia, phosphoric, sulphuric
and silicic acids, and also hydrochlorides. According to Hensel, the
Sudeton, Riesen, Erz, Tichtel, Hartz, Rhone, Vogel, Taunus, Eisel and
Weser mountains, the woods of Thuringen, Spessart and Oden had an
inexhaustible supply of fertilizers. It will be literally possible to
"make bread out of stones." The dust and dirt of our highways also are,
according to Hensel, inexhaustible sources of the same blessing. In this
matter we are laymen and can not test the correctness of Hensel's
theories; a part of them, however, sound most plausible. Hensel charges
the manufacturers of and dealers in artificial fertilizers with
hostility to his discovery and with systematic opposition, because they
would suffer great loss.

According to Heider, a healthy adult secretes on an average 48.8
kilograms of solid and 438 of liquid matter a year. Estimated by the
present standard of the prices of manure, and if utilized without los