M.4ECH 1, 1900.] THE TEOPICAL AGRICULTURIST. 
629 
and ground for market. Dried ground fish, of good 
quality, contains from 7 to 8 per cent, of nitrogen 
together with as much or mere insoluble phosphoric 
acid. 
Meat-scrapF, tankage, etc., are slaughter house re- 
fuse, dried and ground. Good tankage contains 10 
per cent, or more of nitrogen and often 10 per cent, 
or more of insoluble phosphoric acid. 
Nitrogenous guanos are formed in dry regions. 
The Peruvian guano was rich in nitrogen, contain- 
ing 7 per cent, or more. They usually contain 7 to 
12 per cent, phosphoric acid and about 1 per cent, 
potash. 
Bones consist mostly of calcium phosphate of 
lime, which constitutes from one-halt to three- 
fifths of the weight of the bone. The remain- 
ing portion is a soft, fiesh-like substance commonly 
called gelatin, it ia distributed throughout the en- 
tire mass of bone, and is rich in nitrogen. When 
bones are burned, the nitrogenous matter is driven 
off and only the mineral portion or phosphate of 
lime remains. Bones, such as are used in making 
commercial fertilizerv;, contain 4 to 5 per cent, of 
nitrogen, and from 20 to 25 per cent, of phosphovio 
acid, about two-thirds of which is insoluble and 
approximately one-third available. 
Bone-ash is made simply by burning bones in the 
open air. The nitrogen is lost in burning, and the 
chief constituent is insoluble calcium phosphate, equi- 
valent to 30 to 35 or more per cent, of phosphoric 
acid for the most part insoluble. 
Bone-black, known also as bone-charcoal, is exten- 
sively used' in refining sugar. After it has been 
used several times, portions becomes useless for re- 
fining purposes, and are then sold as a fertilizer. It 
ia made by heating bones in closed vessels ; the fat, 
water and nitrogen are driven off, and the bone- 
black remaining consists mainly of insoluble calcium 
phosphate and carbon or obarcoai. Good bone-black 
may contain 30 or more per cent, of phosphoric 
acid mostly insoluble. 
Bone meal goes under various names, such as ground 
bone, bone-flour, bone-dust, etc.. Raw bone-moal 
contains the fat naturally present in bones. The 
presence of the fat is objectionable, because it re- 
tards the decomposition of the bone in the soil, 
while fat itself has no value as plant-food. The 
presence of easily decaying nitrogen compounds in 
bone hastens, in the process of decomposition, to 
dissolve more or less of the insoluble phosphate. 
Bone-meal should contain from 3 to 5 per cent, of 
nitrogen, and from 20 to '2'i per cent, of phosphoric 
acid ; about one-third to one-fourth of the latter ap- 
pears to be in readily available condition. Baw bone- 
meal generally contains somswhat more nitrogen 
(1 to 2 per cent.) and rather less phosphoric acid 
than steamed bone-meal. The fineness of the meal 
affects its value ; the finer the meal the more readily 
available it is for plant-food. 
. Phosphoric Guanos, or Bock Guanos — Guanos 
generally consist chiefly of the dung of sea-fowls, 
though the term is applied to other animal pro- 
ducts. They are generally found in beds resembling 
earthy deposits. The guanos which are called phos- 
phatio contain little or no nitrogen. Their phosphoric 
acid is generally in the insoluble form. These guanos 
come mainly from cert><in islands in the Pacific 
Ocean, and from Caribbean Sea and West Indip.n 
Islands. The phosphoric acid in guanos is very 
variable, ranging from below 15 to over 30 per cent. 
Bock phosphates are known under several different 
names which generally designate the localities from 
which they come, as South Carolina Bock, Florida 
Bock, Tennessee Bock, West India Bock, etc. Other 
forms of mineral phosphates are known under the 
names of apatite, coprolite, phosphorite, which are 
found in various places in America and Europe, and 
some of which are used in making commercial ferti- 
lizers. The rock phosphates are extensively used in 
making acid phosphatea. When ground to a veiy 
fine flour-like powder, rock phosphates are called 
, " floats." Bock Phosphates contain usually from 25 
to 30 per cent, of insoluble phosphoric acid and some 
as mach as 35 to 40 per cent. 
Acid phosphates are known under severel different 
names, such as supeiphosphates, dissolved bone, dis- 
solved rock, dissolved bone, black, etc. Acid phos- 
phates are formed by treating some form of insoluble 
phosphate of lime, as rock-phosphate, bone, bone- 
ash, etc., witti sulphuric acid. By this treatment 
there are formed soluble phosphate of lime and 
gypsum (sulphate of lime) in nearly equal proportions. 
Superphosphate m;ide from rock phosphates may 
contain from 12 to 18 per cent, of available phos- 
phoric acid. 
Thomas slag, also known under several other names, 
such as basic iron slag, Thomas scoria, Phosphate 
slag, etc. It is a by-product formed in the manu- 
facture of iron and steel from certain kinds of iron 
ore containing phosphorus compounds. It usually 
contains between 19 and 20 per cent, of total phos- 
phoric acirl, with 6 to 7 and more per cent, of 
available phosphoric acid. 
Cotton seed hull ashes were pioduced in the 
Southern State of America at the cotton seed-oil 
factories, where the hulls, after being removed from 
the cotton seed, were used as fuel. Such ashes con- 
tain from 15 to 25 per cent, of potash, in addition 
from 7 to 10 per cent, of phosphoric acid. This 
materi^il is not commonly found now. 
Kainit is the most common products of German 
potash mines. It is a mixture of several different 
compounds, containing 11 to 13 per cent, of actual 
potash, together with ab^ut 85 per cent, of common 
salt, also magnesia salts. 
Mariate of potash, also a product of the Stassfurt 
mines, is the main souri e of supply for potash for 
commercial fertilize) s in our market, and contains 
50 to 53 per cent, of actual potash. 
Sulphate of potash is a product of the German 
mines. The product found in the market contains 
from 48 to 51 per cent, of actual potash. 
Sulphate of potash-magnesia is known also as 
double manure salt or low grade sulphate of potash. 
This material comes from ihe German mines and 
contains 26 to 28 percent, of actual potash. It also 
contains 23 to 36 per cent, of sulphate of magnesia. 
Carbonate of cotash-magnesia contains about 18 
per cent, potash and 19 per cent magnesia, both as 
carbonates. It is practically free of chloride. It is 
also a product of the German potash mines. 
Wood-ashes contain more or less potash, which is 
present chiefly in the form of carbonate. The amount 
of potash in commercial wood-ashes varies from be- 
low 4 to 7 per cent., the average being under 5 per 
cent. Wood-ashes also contain between 1 and 2 per 
cent, of phosphoric acid. 
The following are inferior sources of nitrogen. 
They are very slowly available, and should be used 
only where immediate effects are not sought. In some 
states the fertilizer laws either prohibit the use of 
these substances in fertilizers or demand that these 
goods shall be specified when used in making mix- 
tures. 
Hair is obtained from slaughter houses; it is often 
mixed with dried hlo'od and other forms of animal 
matter. It contains about 15 per cent, of nitrogen. 
Hoof-meal and bone dust are by-products contain- 
ing 10 to 15 per cent, nitrogen and about 2 per cent, 
phosphoric acid. They are sometimes treated with 
superheated steam or with sulphuric acid, the treat- 
ment rendering the nitrogen compounds more readily 
available. 
Leather scraps and leather-meal are waste producti 
of various factories. When treated with superheated 
steam and dried or roasted, they can be finely ground. 
They contain 7 to 8 per cent, nitrogen. 
Farm-produced Fertilizing Materials.— Stable or 
farmyard manure consists of the soil and liquid ex- 
crements of animals fed on the farm, mixed with 
straw and wasted products of the farm. 
Horse manure is difiicult to mix thoroughly with 
litter on account of its being very dry. It is called 
a "hot" manure, because, on account of its loose 
texture, it easily undergoes decomposition or fermea. 
