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The other forms of organic nitrogen, i.e., the nitrogen of ani- 
mal and vegetable matters which is chemically united to carbon, 
hydrogen, and oxygen, are— 
Ammoniacal Guanos.—Are the best of the concentrated com- 
plete manures, as they have nitrogen 8 to 12 per cent., phosphates 
15 to 25 per cent., and a little potash. It is a very valuable manure 
for most crops, but is rather expensive. It more nearly resembles 
farmyard manure in its composition than other artificial manures, 
and its great use is to replace this manure when the latter is 
searce. A good dressing, 2 to 3 ewts. to the acre. 
Dried Blood—tThe refuse of slaughter houses, being a very 
complex substance, is also a very valuable manure, and contains 
nearly as much dry matter as flesh—e.g., about 23 per cent. When 
dried without other substances, it contains about 10 per cent. water 
and 8 to 10 per cent. ammonia, with a little phosphate and traces 
of potash. It is one of the best forms of manures in light lands, 
and is not readily washed away. Often mixed with gypsum, which 
decreases its value; useful for making composts. Fair dressing 
per acre, 3 ewt. 
Dried Nightsoil or Poudrette—Contains 2 to 4 per cent. nitro- 
gen, 3 per cent. phosphate, and 1.5 per cent. potash; often mixed 
with gypsum and earth, which reduces its value. A bulky manure 
which would hardly pay to carry a long distance, when freight and 
carriage is a consideration. 
Other forms of organic nitrogen are those of seeds, such as 
cotton seed cake and other oleaginous seeds after the extraction of 
the oil. 
Leather and peat are also classed as nitrogenous manures, but 
they are comparatively slow in their effect on vegetation, and for 
that reason are less valuable. 
Nitrogen occurs as minerals and notably ammonium salts and 
“nitrates” and “nitrites.” 
Sulphate of Ammonia.—Supplies one of the cheapest forms of 
nitrogen in the market. When pure, contains 24 to 25 per cent. of 
ammonia, equivalent to 20 of nitrogen, and is one of the most 
concentrated forms of nitrogen available. It is obtained from coal 
gasworks and extracted from the gas liquor, and is purified of the 
ammonia thiocyanate (a plant poison) it contains before being put 
on the market. As it is not quite so soluble as nitrate of soda, 
it is not so liable to be washed out of the soil as are nitrates. A 
simple test for showing the absence of most, at any rate, of the 
impurities with which sulphate of ammonia is likely to be adulter- 
ated is to throw a pinch of the sulphate on a red hot iron plate; 
the sulphate of ammonia, if pure, will be quickly volatilised and 
dissipate entirely. Applied at the rate of % to 114 ewt. per acre 
