Nitrogen compound

“ The results under proper conditions are accurate even when a small quantity of nitric nitrogen is present. When, however, there is any considerable quantity of this compound in the sample the method becomes inapplicable by reason of non-reduction of some of the nitrogen oxids produced by the combustion.
In bodies very rich in nitrogen such as urea all the nitrogen is not transformed directly into ammonia at the commencement of the combustion. A portion of it may unite with a part of the carbon to form cyanogen, which may unite with the soda to form sodium cyanid. ”

“ The nitric acid, as it becomes free, gives a part of its oxygen to the phosphorous compound, and the nitrous acid, in a nascent state, is at once reduced by the ammonium chlorid. There are two sources of error which must be guarded against in the work; a portion of the nitrogen may escape reduction to the elementary state, or some of the nitrate may fail to be decomposed. These errors are easily avoided if the reaction be begun slowly, so that the evolution of gas may be gradual. ”

“ The carbon atom has four hands, and atoms of nitrogen and phosphorus have five hands, but sometimes use only three. Thus, in the compound called ammonia, one atom of nitrogen always holds three atoms of hydrogen; so, if you buy seventeen pounds of ammonia you would get only fourteen pounds of nitrogen and three pounds of hydrogen. This means that, if the two-eight-two fertilizer contains two per cent. of ammonia, it contains only one and two-thirds per cent. of the actual element nitrogen, and a ton of such fertilizer would contain thirty-three pounds of nitrogen. ”

“ The free nitrogen of the air cannot be utilized directly by plants. It must first be converted into some combination with other chemicals, as a solid or liquid, which can be absorbed by the plant. Among others who worked on the problem of fixing atmospheric nitrogen were two German chemists, Doctors Caro and Frank, who found that a compound of calcium and carbon heated to a high temperature would absorb nitrogen and retain it in a form that could be applied to the soil and serve as a food for plants.
Sugar Cane Crop Fertilized with Cyanamid Mixtures. ”

“ While it is true that plants can absorb nitrogen in certain organic forms and as ammonia salts, it is now a well-known fact that the chief, and by far the most important, source of nitrogen is nitric acid. Probably more than 90 per cent of the nitrogen absorbed by [Pg 51] green-leaved plants from the soil is absorbed as nitrates. The tendency of all nitrogen compounds in the soil is towards conversion into nitric acid. It is the final form of nitrogen in the soil. ”

“ As regards the first alternative, it must be stated that we know of no source other than the decomposition of plants from which ammonia can be derived, and we are therefore compelled to adopt the second alternative, and to admit that there must be some other source of nitrogen, and it cannot be doubted, from what has been already stated, that it is from nitric acid only that it can be obtained. ”

“ Nitric acid is one of the strongest known, and in solvent power it is excelled by no single acid. The nitrogen contained in crop residues and other organic manures is chiefly in chemical combination with carbon, oxygen and hydrogen, much of it in insoluble protein compounds. Normally this organic nitrogen is transformed in the soil, first into ammonia nitrogen, next into nitrite nitrogen, and lastly into nitrate nitrogen, these three transformations being effected by biochemical action produced by different kinds of living microscopic organisms called bacteria. ”

“ For after the mephitic portion is absorbed by a caustic alkaline lixivium, the remaining portion is not rendered salubrious; and although it occasions no precipitate in lime-water, it nevertheless extinguishes flame and destroys life." Such is the doctor's account of the discovery of nitrogen, which may be separated from the oxygen in the air in a very simple manner. The atmosphere is the great storehouse of nitrogen, and four-fifths of its prodigious volume consist of this element. ”

“ The organic nitrogen may be in a form easily nitrified and rendered available for plant food, or it may be inert and resistant to nitrification, as in humus, or exist in an amid state. The ammoniacal nitrogen may exist in small quantities as gaseous ammonia, or be combined with mineral or organic acids. As nitric or nitrous acid the nitrogen will be found combined with bases, or perhaps in minute quantities as 421free acid, in passing under the influence of the nitrifying ferment from the organic to the inorganic state. ”

“ We have already made some reference to this gas when speaking of the atmosphere and its constituents, of which nitrogen is the principal. From its life-destroying properties it is called “azote” by French chemists, and when we wish to obtain a supply of nitrogen all we have to do is to take away the oxygen from the air by burning phosphorus on water under a glass. Nitrogen is not found frequently in solid portions of the globe. It is abundant in animals. It is without colour or smell, and can be breathed in air without danger. ”

“ Such a case would be presented for instance, in that of a fertilizer containing dried blood, sodium nitrate, and ammonium sulfate. It is evident here that the total nitrogen could be determined by the volumetric method by combustion with copper oxid, or by the moist combustion process adapted to nitric nitrogen, but the method of determining the percentage of each constituent has not yet been described.
We have to deal here with a case entirely similar to that of phosphoric acid in a superphosphate. There is no doubt whatever of the uneven assimilability of the different forms of nitrogen. ”

“ A variety of nitrogenous substances have proved susceptible to nitrification in solution. The weight of evidence, however, appears to show that in all cases the nitrogen first assumes the form of ammonia, and that the latter is, strictly speaking, the only substance capable of being nitrified. ”

“ But it is also possible that some direct oxidation of protein or amino-acids may yield gaseous nitrogen. However it is brought about it affects a considerable proportion of the entire stock of nitrogen, and it becomes more serious as cultivation is intensified. ”

“ It is much more probable, however, that it depends on small quantities of ammonia or nitric acid which had not been completely removed from the air by the means employed for that purpose, for nothing is more difficult than the complete abstraction of these substances, and as the gain of nitrogen was only 0·8 grains, while 60,000 gallons of air, and 13 of water, were employed in the experiment, which lasted for a considerable time, it is reasonable to suppose that a sufficient quantity may have remained to produce this trifling increase. ”

“ This is the general process of nitrification in which the nitrifying bacteria transform or transfer the nitrogen from insoluble organic compounds into soluble compounds in which it may serve as available plant food. The nitrate which is thus formed may be calcium nitrate or magnesium nitrate or potassium nitrate or even sodium nitrate, depending upon which of these alkaline elements is present in the must suitable form. If no alkaline element is present in available form then no nitrates can be made in the soil. ”

“ It is the character of nitrogen to refuse chemical combinations. Uncombined nitrogen is nowhere available for vital uses, to any appreciable extent. Filling perfectly its humble service in Nature as a diluent in the air, its qualification is to be inert and to remain changeless. Among the resources of life and in the marts of subsistence where its compounds rank high in value, nitrogen as a simple has no place at all. ”

“ Nitrogen is slightly lighter than atmospheric air, and is fourteen times as heavy as hydrogen. It is but slightly soluble in water, one hundred volumes of water at ordinary temperature dissolving only one and a half volumes of nitrogen. ”

“ Of the adequate resources, nitrogen is needed by the largest number of living bodies and used in the largest quantities. It enters into most animal tissues and the more complex of the vegetable products; being two and a half parts in a hundred of the body of man, or eight per cent, of its solids. It is obtained for the organic world solely by the plants, and obtained only from combinations of nitrogen, the ammonia and nitrates of the air and the soil. ”

“ Nitrogen may be most easily obtained for experiment by setting fire to some phosphorus contained in a porcelain or metallic cup, placed under a gas jar full of air, and resting on the shelf of the pneumatic trough, or in a soup-plate filled with water.
Nitrogen combines in five different proportions with oxygen producing five distinct chemical compounds, named respectively nitrous oxide, nitric oxide, nitric tri-oxide, nitric tetroxide, nitric pent-oxide, which last, united with water, forms nitric acid, now called hydric nitrate, as nitrous acid is termed hydric nitrite. ”

“ Upon such occasions, the severity of our disappointment will always be in proportion to the importance of the object we desire to accomplish; and it is impossible not to feel that the discovery of the true nature of nitrogen would lead to new views in chemistry, the extent of which it is not easy even to imagine.
The principal objects of research which this paper embraces are,—the elementary matter of ammonia; the nature of phosphorus, sulphur, charcoal, and the diamond; and the constituents of the boracic, fluoric, and muriatic acids. ”

“ It is not probable, however, that the difficult task of oxidizing atmospheric or free nitrogen would be accomplished in nature in only one way. In fact it has already been established that organisms do exist which are capable of oxidizing free nitrogen in a manner wholly independent of other plant life and to produce weighable quantities of nitric acid when developed in media of mineral matters and pure carbohydrates to which free nitrogen has access. ”

“ By exposing nitrite of ammonia to heat in a retort, nitrogen comes over alone in great abundance; for the hydrogen of the ammonia is sufficient to saturate the oxygen of the acid, and to convert it into water; while the nitrogen of both constituents is set at liberty. By transmitting chlorine through water of ammonia, or digesting lean flesh in warm nitric acid, nitrogen may also be obtained. This permanently elastic gas is destitute of colour, taste, and smell; it has a specific gravity of 0·976, air being 1·000. ”

“ Hence, although this gas is present in the atmosphere surrounding the plant, the147 plant will perish if nitrogen does not exist in some combined form in the soil. Nitrates and compounds of ammonia are widely distributed in nature, and it is from these bodies that the plant obtains, by means of its roots, the necessary nitrogen. ”

“ Nitrogen is a substance also generally diffused through nature, and particularly in animal bodies, and causes great changes in those absorbing or exposed to it. This gas, combined with oxygen and hydrogen, produces neither light, heat, nor combustion, but serves to dilute the others: of itself, it is hurtful to animal life. Nitrogen makes the principal part of the salt we call nitre. ”

“ Nitrogen, itself, is an inert gas of no particular use, but nitrogenous compounds are necessary to agriculture, to refrigeration, to munitions manufacture, and to the applications of chemistry in general. In the native gaseous state, it makes up about four-fifths of the atmosphere, and combined it occurs as nitrate minerals, as organic compounds, and in carboniferous deposits. ”