how to so treat these insoluble [phosphates as 
to render them readily soluble, and thus avail¬ 
able food for the plant. We have before shown 
how soluble phosphoric acid, by the addition 
of lime, becomes insoluble phosphate of lime. 
Now, if by any means we can take from this 
latter eompouud a part of the lime, we shall 
again have soluble phosphoric acid. This can 
easily be done by the use of sulphuric acid. 
Lime has a greater affinity for sulphuric acid 
than for phosphoric acid; so, if to finely 
powdered phosphate of lime we add sulphuric 
acid and water, in the proportion of four 
atoms of the phosphate, two atoms of water 
and one of sulphuric acid, the atom of acid 
will wrench one atom of lime from its union 
with the phosphoric acid, aud uniting with the 
other atom of water, will take the place of 
the atom of lime in the phosphate, forming 
again the compound before described as the 
dicalcic phosphate of lime, or what is de¬ 
scribed as reverted phosphate. If to this com¬ 
pound there be now added anorber atom of 
sulphuric acid and two more atoms of water, 
the sulphuric acid will divorce another atom 
of lime from its uuion with the phosphoric 
acid, and uniting with it and an atom of the 
water, will form auotber atom of gypsum. 
The other atom of water will take the place of 
the divorced lime, forming again the mono- 
calcic or one lime phosphate, which, will be 
like the monocalcic first described, only that 
the one atom of lime and the one atom of 
phosphoric acid and the two atoms of water 
constituting it, instead of being pure as there 
set forth, will now be intimately mixed with, 
but not in any way united to. two atoms of 
gypsum or land plaster. But though so mix¬ 
ed, the superphosphate of lime is entirely and 
readily soluble and available as plant food. 
This is the superphosphate, or acid phosphate, 
of the trade, and it made of pure materials 
will have 1,000 pounds of phosphate of lime iu 
the form of bone ot phosphatic rock.800 pounds 
of sulphuric acid and 400 pounds of water 
mixed together; but it will have lost 200 
pounds of water by the process of mixing and 
uniting, leaving just one tou. This should con¬ 
tain 500 pounds of monocalcic or ODe lime 
phosphate, one half (250 pounds) of which will 
be phosphoric acid; 500 pounds of gypsum, 
750 pouuds of water and 250 pounds of var¬ 
ious impurities and other matters which were 
in the bone or phosphate. This would show 
12X per cent phosphoric acid. 
REVERTED PHOSPHORIC ACID. 
When acid phosphate is applied to the soil so 
strong is the affinity of the phosphoric acid 
for more lime, that if there is available lime 
in the soil, or if not, if there is anything 
in the soil having only a slight affinity 
for sulphuric acid,either will bjsuffieient to en¬ 
able the monocalcic (one-lime) phosphate to 
take another atom of lime and thus become the 
dicalcic (two-lime) phosphate, which is what is 
known as reverted phosphate, and though in¬ 
soluble in water it is still soluble in the weak¬ 
er acids and available food to the plant. It is 
quite likely that this is the form io which the 
plant takes its whole supply. 
ALKALINE SUPERPHOSPHATE. 
What is sold as the above is the before men¬ 
tioned superphosphate,mixed with more or less 
of some of the various potash salts insufficient 
quantity to give the stated quantity of potash; 
but when the potash, is quoted iu the published 
analysis, as “potash salts,” the term is very 
misleading, as without chemical tests no one 
can tell whether the potash salts is kaiuft, 
sulphate or muriate or carbonate; or whether 
it contains 6, 12>£, 25, or 50 par cent, of actual 
potash. 
ammoxiatkd superphosphate. 
If the before described superphosphate was 
made from raw bones, it would contain, in the 
gelatine and animal matter of the bones, suffi¬ 
cient nitrogen to show in the manufactured 
article anywhere from 1)4 to 8$ [per eeut. of 
ammonia. If made from bone ash or from 
mineral phosphate, the manufacturers supply 
in dried blood, tankage, fish scrap, nitrate of 
soda or sulphate of ammonia, a sufficient 
quantity so that the phosphate show6 the per¬ 
centage of ammonia shown in the analysis. 
This is the aminoniated phosphate sold on the 
markets. 
SOUTH CAROLINA PHOSPHATES. 
The phosphatic rock which is extensively 
used in many sections as a fertilizer, is found 
along the coast of South Carolina. This coast 
is remarkably low and flat, and intersected 
by many sluggish streams and lakes. The 
phosphatic deposits extend from the head¬ 
waters of the Wando River — a few miles 
above Charleston—to the bead waters of the 
Broad. This tract lies more or less parallel 
to the coast line, with a width of from 10 to 
40 miles. This is the section of active opera¬ 
tion, though it is quite probable that the de¬ 
posits extend into North Carolina, and as far 
south as Florida. Indeed, large deposits have 
lately been found in North Carolina and also 
Pn Alabama. The phosphatic stratum occurs 
at different depths. At some places it crops 
out iu the top soil, while in many others it is 
found 10 to 20 feet below the surface. At 
Charleston it is 60 feet below. Various theo¬ 
ries are advaueed as to the origin of these 
phosphates. Prof. F. S. Holmes regarded 
them as detached pieces of Eocene marl torn 
off by the waves and swept inland. He claims 
that the internal structure of the marl and 
phosphate is identical, both containing the 
same remains of marine vertebrates, etc. The 
theory is that the salt water lakes or bays 
became lagoons frequented by laud animals. 
Their feces and remains were the cause of the 
conversion of the carbonate of lime, or marl 
masses, into the phosphate rock. Teeth and 
bones of various land animals—some of them 
extinct—are found in the rock. 
The most prominent characteristic of these 
phosphates is their nodular form. The rock is 
made up of egg, or kidney-shaped masses 
varying from an inch to several feet in diam¬ 
eter, and in weight from a ton downwards. 
These masses are devoid of any crystalline 
structure or cleavage. The average specific 
gravity is 2 4. The rock can be easily ground 
to a powder, ligbt-yellow or gray in color. 
On friction of its fresh surface, the phosphate 
gives a peculiar, fetid odor. Prof. Cbas. U. 
Shephard, from whose treatise these facts are 
taken, gives as the result of many hundreds 
of analyses, the following as a general state¬ 
ment of the average amount of the most im¬ 
portant chemical constituents. _ 
1*EK CENT. PEE CENT. 
Phosphoric acid (1) - - 25 to 28 
Carbonic acid i8) - - • - - - 214 “ 5 
Sulphuric acid " 2 
Lime 85 “ 42 
Magnesia - traces “ 2 
Alumina.“ “ 2 
S squloxde ot iron - - 1 “ 4 
.Fluorine 1 2 
Sand and silica .... 4 “ 13 
Organic matter and comb, water 2 “ 6 
Moisture ------ M “ 4 
(1) Equivalent to bone phosphate of lime 55 to 61 
per cent. 
(2) Equivalent to carbonate of lime 5 to 11 per cen 
The thickness of the nodular stratum aver¬ 
ages about eight inches, varying from four to 
thirty. The average yield per acre is about 
800 tong. The land beds are excavated by 
means of pick and shovel. The rock is washed 
free from dirt aud then dried and crushed, 
ready for shipment. The river deposits 
are secured by hand picking or dredging. The 
rock is dried by means of hotair contrivances 
or by piling in the sud. The following ad¬ 
vantages are claimed for this phosphatic rock: 
—It is cheap. It is remarkably free from 
impurities. It is readily ground. It contains 
little fluoride of calcium aud thus yields less 
noxious fumes than most apatitic phos¬ 
phates. The assimilation of its constituents 
by plants takes place more rapidly and effect¬ 
ually (without the intervention of sulphuric 
acid) than with most other mineral phosphates. 
Prof. Shepard estimated the total yield of all 
known phosphatic deposits of (South Carolina 
at 5,000,006 tons. Mr. E. Willis, of Charles¬ 
ton, South Carolina, states that up to May 
81st, 1885, 2,682,620 tons of rock bad been 
shipped from ports in South Carolina. In 1876 
the total shipment was 182,626, while in 18S5 
it was 895,403 tons. Of the whole amount 
1,062,482 tons were sent to foreign countries. 
APATITE AND PHOSPHORITE, 
are two forms of mineral phosphate of lime, 
the apatite occurring largely in mines in Can¬ 
ada and Norway, and more sparingly in the 
States of New York and New Jersey. The 
phosphorite exists in immense quantities iu 
Spain. They both contaiu large quantities of 
phosphoric acid equivalent to 00 to 80 per cent, 
of bone earth and are readily reduced to the 
soluble form by the use of sulphuric acid, and 
the superphosphate resulting would contaiu 
from 13 to 19 per cent of phosphoric acid. 
The available supply from the various de¬ 
posits must be immense where they are fully 
worked. 
COMPLETE MANURES 
contain phosphoric acid, ammonia and potash 
in varying quantities, according to the sup¬ 
posed needs of the soil and the crop to be 
grown, and they are made by adding to the 
soluble phosphate some one of the nitrogenous 
compounds above mentioned, and also some 
one of the potash salts; but when we consider 
the great variations in the character of soils 
and the equally different composition of the 
growing plants, it will be easy to see that 
what might be a complete manure for one soil 
or crop, might lack much of being so for an¬ 
other. This basled to the making of manures 
for special crops and special soils. 
We have thus given a clear description of 
hosphorus and phosphoric manures in plain 
language, free from all scientific terms, and 
while not intending to discriminate for or 
against any, have tried to enable the ordinary 
reader to understand how and from what they 
are made. 
POTASSIC MANURES. 
POTASH. 
Pure potash is the rust or oxide of the 
metal potassium, and, as found in commerce, 
it is combined with water in equal parts, aud 
as such,is a white, opaque, corrosive substance. 
It exists in, and is essential to the growth of 
every known plant, forming a large percent¬ 
age of its ash. Though found in all soils, it is 
often in quantities too small to produce the 
best crops, or it may be, in such a combination 
as to be locked up and unavailable as a plant 
food. Light sand and sandy loam are most 
likely to be deficient in the supply of potash. 
Mucks or peats that have been much flooded 
or washed, have their potash, iu combiuttlion 
with other things, locked up iu the vegetable 
fiber; nearly all that, previously liberated by 
the decay of fiber, having been washed out. 
Formerly a large part of the potash of com¬ 
merce was obtaiued from the ash of plants, 
by lixiviation and the boiliug down of the 
lye. And in some countries much can still be 
obtained by the farmer for his use in 
hard wood ashes. These, if good, con¬ 
tain about five to six per cent, of potash, 
and, as this is the firm of carbonate, it is 
more available to the plant, and is consequent¬ 
ly more valuable than in any other form; and 
where these ashes can be purchased at a price 
which will aff >rd the potash at five or six 
cents per pound, the farmer can do no better 
than to buy them in n large way. An ordin¬ 
ary bushel of dry ashes (50 pouuds) will con¬ 
taiu from 2)4 to pouuds of actual potash 
At present tbe great bulk of potash, used 
in the arts, and fertilizing as well, is obtained 
from potash salts—potash iu combination with 
some acid. Natural deposits exist in immense 
quantities in Germany as is now known, and 
no doubt in other countries as will be found by 
and by when further search is made. 
- M l 
MURIATE OF POTASH. 
Muriate of potash is a substance much re¬ 
sembling common salt and is a combination 
of potash (oxygeu and potassium) with muri¬ 
atic acid, (chlorine and hydrogen) so that pri¬ 
marily it contains four of the elements of 
plant growth. 
Iu 1857, in boring for salt near Stassfurt, 
Germany, at the depth of 1,018 feet, a very 
extensive deposit of carnalite (a crude mu¬ 
riate of potash) was struck. Its value as a 
source of potash was not discovered until 
some years later, and in 1863,only about 13,000 
tons were taken out. It has, however, been 
growing in importance, until last year over 
150,000 tons were taken, and its use is very 
rapidly extending, the supply seeming inex¬ 
haustible. 
As mined, it is mixed with soda, magnesia, 
sulphur, etc., and in preparing it for use as a 
fertilizer, 0)4 tons of the raw material are 
required to make one ton of the muriate 
containing 80 per cent, of pure muriate of 
potash, or 50.54 per cent, of actual potash. 
While 80 per cent, is the standard of purity 
by which it is sold, it usually runs much high¬ 
er, eveu up to 98 per cent, with a correspond¬ 
ing 62 per cent, of actual potash. As now 
manufactured, it is very free from any in¬ 
gredients injurious to vegetation, being 
guaranteed to contain not more than one-half 
of one per cent, of the injurious chloride of 
magnesia. 
This form of potash salt therefore contains 
more actual potash than any other salt at 
present available. It may be applied with 
advantage on most soils and is especially 
recommended for potatoes, corn, clover, peas, 
beans, flax, aud also for fruit trees. It is 
particularly advised that it should be applied to 
peach tress, rendering them very vigorous and 
imparting a very fiae color to the fruit. It is 
thought by many to be almost a specific for 
tbe peach yellows, 100 to 150 pounds per acre, 
being one of the ingredients recommended by 
Prof. Peuhallow. When used alone, it should 
be made free from lumps and sowed broad¬ 
cast, aud at the rate of from 100 to 300 pounds 
per acre; some people in New England use as 
much as 600 or 700 pouuds on peach orchards. 
It is easy for any one to calculate the cost of 
actual potash when purchasing this salt, as its 
price is always fixed on tbe basis of its con¬ 
taining 80 per cent, muriate of potash, and as 
this contains practically one-half its weight 
in actual potash, if the price per pound paid 
be doubled, it will give the cost of actual 
potash. 
There is much difference of opinion as to 
whether muriate or sulphate of potash is the 
better form in which to present potash for the 
use of the crops; but this question we will 
leave open for further discussion, and will 
welcome an article from the friends of either 
salt setting forth its claims. 
SULPHATE OF POTASH. 
Sulphate of potash is a white crystalline 
substance, or it may be finely powdtred, and 
is formed by a uuion of potash (potassium and 
oxygeu) with sulphuric acid (sulphur und oxy¬ 
gen), so that primarily this salt consists of 
only three elements—potassium, oxygen and 
sulphur. It is much less soluble in water 
than either tbe muriate or carbonate. It ex¬ 
ists in common alum to tbe extent of 18 per 
cent., is in nearly all soils, and in the ashes of 
all plants. It has also been largely found in 
the mines of Germany, from which the sup¬ 
ply is now obtained. 
It is manufactured from kainit, and, as put 
upon tbe market, contain®, on an average, 
about 25 per cent, of actual potash A grade 
is, however, manufactured called the bisul 
phate, or double snlphata, which contains 
sometimes nearly 50 per cent, of actual pot¬ 
ash. This form of potash is claimed to be 
preferable for use on berries, grapes and 
other sweet fruits, developing a greater pro 
portion of sugar tbau the use of the mm-iate; 
but this question is not conclusively settled, 
being, as we believe, one of the matters under 
consideration in certain experiments now be¬ 
ing made uuder the supervisou of Dr. G. C. 
Caldwell, of Cornell University. When it is 
to be applied to the soil.it should be rendered 
as fine as possible and be sowfi broadcast, and 
in order to apply as much potash per acre as 
in muriate, if the ordinary sulphate i8 used, 
twice the quantity p?r acre is needed. 
WOOD asheb. 
When burned, from 1.5 to six per cent, of 
all trees will remain, the residue containing 
the fixed elements of ihe trees and known as 
wood ashes. These contaiu, among other 
things, the lime, potash and phosphoric acid 
of the plants. 
While the ashes of all conifers and resinous 
trees contain scarcely sufficient of either pot¬ 
ash or phosphoric acid to pay for their appli¬ 
cation, eveu where already on the premises, 
the ashes of deci ‘uous trees are a valuable 
fertilizer, for they contain from three to nine 
per cent, of potash and from one to three per 
cent, of phosphoric acid; and as the potash 
exists as a carbonate, it is very valuable as a 
plant food. In many puts of the country 
ashes are still quite abundant, and where they 
can be purchased at 20 cents or less per 
bushel of 50 pounds, are a cheap source of 
potash and phosphoric acid, and should be 
largely used by the farmer. Leached ashes 
have little potash left, and aside from the 
phosphoric acid, which nearly all remains, are 
only valuable for their mechauical effect. 
kainit 
also comes from the mines of Germany near 
Stassfurt. It is the crude sulphate, as car¬ 
nalite is the crude muriate of potash, and is 
only broken aud crushed after being mixed, 
to fit it for exportation. It contains very 
uniformly about 12 5 per cent, of actual pot¬ 
ash, equivalent to 22!^ to 23J^ per cent, of sul¬ 
phate. Besides this, it contains nearly 50 per 
cent, of chloride of sodium or common salt, 
also magnesia and sulphur. Its use is on the 
decrease, sulphate and muriate taking its 
place; yet it is a valuable manure for grass 
land aud for potatoes, and is especially desir¬ 
able to scatter in stables and over manure 
piles and in other places as an absorbent. 
When applied to the soil for any spring crop, 
it is bettor if applied in the pi'evious Fall, so 
that it may have time to become thoroughly 
mixed with the soil. On some soils it pro¬ 
duces good results, but unless sold cheap it is 
better to substitute either the sulphate or 
muriate. 
cotton seed hull ashes. 
These should not be overlooked as a means 
of obtaining potaih, especially bv our friends 
iu the cottou-gro wing States. Where the hulls 
are used as u fuol in the oil mills, alone or in 
connection with wood, the ashes are very rich 
in potash, often containing as much as 24 to 
30 per cent., aud eveu higher. They also con¬ 
tain from five to uine per cent, of phosphoric 
acid, so that where they can be bought at 
the average price at which they are sold at 
the mills, they are worth applying. 
NITROGENOUS MANURES. 
NITROGEN. 
What is it—where is it stored, and how 
can it be obtained for use as a fertilizer? 
Nitrogen is an invisible gas without taste or 
smell, aud when pure it has no visible effect 
upon plants or animals, and yet it is indispen¬ 
sable to the existence of either. The atmos¬ 
phere is the great repository of this gas, being 
a mechanical mixture of nitrogen and oxy¬ 
gen, in the proportion of four parts of the 
former and one of the latter, each practically 
free and uncombined with the other. When 
we consider the immensity of this great ocean 
of air extending, as it does, on every side and 
to a depth of at least 15 miles, and with a 
weight of 15 pouuds on every square inch of 
the earth’s surface, four-fifths of which, or 
over 11)4 pounds, per square inch, is pure 
nitrogen, we get some faint conception of the 
millions aud millions of tons of this very es 
1 element of growth.which[exists^every ; 
