Vermont watchman and State journal. [volume] (Montpelier, Vt.) 1836-1883, 1875-04-21
" Popular Science"

popular Science"
Any reader OF our Eastern agricultural papc
secs frequent allusi0us made to phogahdfcs m
sipCiphoYhdfes. The former word merely meal
dccomposed bones or the carbonate Of lime 81
pef7hOSphdtc is a scientific preparation uf this ma
tcrial for fertilizng, and Is two parts bone, oi
part sulphuric acid, and three parts water H.
We find the above scrap Of mis-informa
ton in an agricultural exchange. Now
a-days chemistry is taught in all our acad
emies and many of our public schools vel
it is perhaps asking too much to require that
editors Of agricultural papers should know
ANYTHING about science more closely inter
woven with successful agriculture than any
other Certainly we would not advise an
agricultural editor who. at a county fair, had
to inquire which were the Shor-horns aud
which the Jerseys, to make chemistry his
inst study. But roud it be 90 mulch, rs
the lamcnted A. Ward would say. to expect
that an editor, evidently ia total Oblivion as
regards the first lines of agricultural chem
isiry. would marcifully forbcar attempting TO
give instruction therein, either at first or
second hand
The first sentence in the above extract is
probably correct It is Something 10 have
the exorditm Of scientific lecture in &C
cord with facts But the two succeeding
sentences contain six very stupid errors, and
not a single approximation to the truth.
d" Phosphate does not mean decomposed
homes it does not mean carbonate Of lime.
" Superphosphate is not a scientific prep
araiion Of carbonate Of lime; it is not two
parts or any part bone; it contains no sui
phuric acid and no water
Perhaps it may be as well not to stop here
but to say briefly just what "phosphates
and d" superphosphates of lime are They |
are both of them compounds Of an acid called |
phosphoric acid, with lime. Phosphoric |
acid is itself compound Of PHOSPHORUS
(Which we are all familiar with as being
used in the tips Of friction matohes) with |
the oxygen Of common air. Phosphoric
acid is produced when Phosphorus is
burned; in a pure form it appears as
white powder, which, dissolved in water, has
a very sour taste Phosphorc acid com
bines with other bases besides lime, and
these compounds are all called phosphates;"
a fact evidently unknown to the writer of |
the above extract. With lime it makes
three distinct compounds or phosphates, as
follows:
Three parts lime, one part phosphoric acid. |
Two parts lime one part phosphoric acid.
a m IN arf ftl naf.ltp rio uaiA
The first Of these phosphates or three
lime phosphate" is the phosphate which is
found in bones and in the phosphate min
erals used for making fertilizers; such as the
South Carolina phosphate and the phosphate
rocl, called "apatite." 1t is insoluble in |
water, and consequently useless as a fertilizer
until it is in some way changed so that
water can dissolve it, since plants always |
take their food in a fluid form.
The second compound Of phosphoric acid |
and lime, or "two-lime phosphate" is a
somewhat rare substance, aud is also nearly |
insoluble in water.
In order to make the phosphate Of lime in
bones and mineral phosphates useful as
fertilizer, it must be made soluble in uaier |
and this is done by changing it into the |
third compound, or "one-ime phosphate" |
called also superphosphate," and soluble
phosphate" To effect this it is necessary 10 |
deprive the three-lime phosphate " of two
parts of its lime, which is done by the use
Of sulphuric acid, otherwise called oil Of
yitriol." When sulphuric acid is added to
ground bones or pulverized mineral phos-
phate of lime,-" threelime phosphate it
takes away from il two parts Of the lime
which it contains, and unites with that lime
to form substance called "sulphate of
lime This substance is also called "plas-
ter" or Gypsum" which most farmers are
familiar with. When the mixture is com
plete, the proper proportions having been
used, the mass consists of one-lime or solu- |
bic phosphate sulphate OF lime and the
other substances which wore contained in
the bones or the mineral. About one-half
the material of bone consists of three-lime
phosphate" the rest being mostly animal
matter containing nitrogen, which is also
valuable as a fertilizer.
The "superphosphate which results from
the above described process consists simply
of one part of phosphoric acid and one part
of lima. 1t does not contain any bone"
for that has been decomposed. 1t doss not
contain any sulphuric acid, for that is com
bned with the lime to make suphate of
of lime. Neither does it contain any water
1t is just simply lime and phosphoric acid,
united together, in equal parts, by weight.
But the whole mass which is what is sold
as fertilizer under the commercial name of
superphosphate of lime" contains the true
or pure superphosphate mixed with the sui
phate of lime, and with the animal matter
and other ingredients of the bones that were
used to make it. 1t is an unusually good
commercial superphosphate that contains
over twenty-five per cent, or one quarter, by
weight, of pure superphosphate of lime.
The rest (supposing no adulteratng or other
fertilizing substances have been mixed with
it, consists Of sulphate of lime, etc, as men
toned above. No properly made CONNER
cial superphosphate contains a particle of
" carbonate of lime" which is simply com
mon limestone or air-slaked lime.
Congress and the Farmers.