AMMONIA. 



AMMONIA. 



" Ammonia, therefore, must have yielded the i 

 nitrogen to these plants. Gluten is obtained ' 

 not only from corn, but also from grapes and ] 

 other plants ; but that extracted from the grapes 

 is called vegetable albumen, although it is 

 identical in composition and properties with 

 the ordinary gluten. 



"It is ammonia which yields nitrogen to^the 

 vegetable albumen, the principal constituent 

 of plants ; and it must be ammonia which 

 forms the red and blue colouring matters of 

 flowers. Nitrogen is not presented to wild 

 plants in any other form capable of assimila- 

 tion. Ammonia by its transformation, fur- 

 nishes nitric acid to the tobacco plant, sun- 

 flower, Chenopodium, and Borago officinalis, 

 when they grow in a soil completely free from 

 nitre. Nitrates are necessary constituents of 

 these plants, which thrive only when ammonia 

 is present in large quantity, and when they are 

 also subject to the influence of the direct rays 

 of the sun, an influence necessary to effect the 

 disengagement within their stem and leaves 

 of the oxygen, which shall unite with the am- 

 monia to form nitric acid. 



" The urine of men and of carnivorous ani- 

 mals contains a large quantity of nitrogen, 

 partly in the form of phosphates, partly as 

 urea. Urea is converted during putrefaction 

 into carbonate of ammonia, that is to say, it 

 takes the form of the very salt which occurs 

 in rain-water. Human urine is the most pow- 

 erful manure for all vegetables containing 

 nitrogen ; that of horses and horned cattle con- 

 tains less of this element, but infinitely more 

 than the solid excrements of these animals. In 

 addition to urea, the urine of herbivorous ani- 

 mals contains hippuric acid, which is decom- 

 posed during putrefaction into benzoic acid 

 and ammonia. The latter enters into the com- 

 position of the gluten, but the benzoic acid 

 often remains unchanged ; for example, in the 

 Anthoxanthum odoratum. The late Professor 

 Gorham obtained from Indian corn a substance 

 to which he gave the name Zeine, according to 

 whose analysis it contains no nitrogen; but 

 ammonia has since been obtained from it." 



It has always bren a popular opinion 

 among husbandmen, that snow contained some 

 fertilizing salts, as winter crops were gene- 

 rally observed to thrive best after being long 

 covered with snow. Common observation is 

 here fully sustained by science, since ammo- 

 nia, one of the greatest of fertilizers, may 

 always be detected in snow-water, the inferior 

 layers next the ground containing the largest 

 proportion. 



The following interesting calculation is 

 given by Liebig. " If," says he, " a pound of 

 rain-water contain one-fourth of a grain of 

 ammonia, then a field of 40,000 square feet 

 must receive annually upwards of 80 pounds 

 of ammonia, or 65 pounds of nitrogen ; for, by 

 the observations of Schiibler, which were for- 

 merly alluded to, about 700,000 pounds of rain 

 faH^ver this surface in four months, and con- ' 

 seqtftntly the annual fall must be 2,500,000 j 

 pounds. This is much more nitrogen than is ! 

 contained in the form of vegetable albumen , 

 and gluteo, in 2,650 pounds of wood, 2,800 j 

 pounds of hay, or 200 cwt. of beet-root, which ; 

 82 



are the yearly produce of such a field, but it is 

 less than the straw, roots, and grain of corn 

 which might grow on the same surface would 

 contain." 



As to the source from which the ammonia 

 diffused in the atmosphere is derived, it is suf- 

 ficient to refer to the fact that ammonia is the 

 last product of the putrefaction of animal bo- 

 dies, all of which, whether large or infinitely 

 omall, yield their nitrogen to the atmosphere 

 in the. form of ammonia. This cannot remain 

 long in the air, as every shower of rain must 

 absorb and convey it to the earth. " Hence also, 

 rain-water must, at all times, contain ammonia, 

 though not always in equal quantity. It must 

 be greater in summer than in spring or in 

 winter, because the intervals of time between 

 the showers are in summer greater ; and when 

 several wet days occur, the rain of the first 

 must contain more of it than that of the 

 second. The rain of a thunder-storm, after a 

 long protracted drought, ought for this reason 

 to contain the greatest quantity which is con- 

 veyed to the earth at one time." 



Is it asked what direct proof exists that 

 ammonia acts so favourably in promoting 

 vegetation? The answer is furnished in the 

 results of experiments made by Sir Humphry 

 Davy, in which the beaks of retorts containing 

 fermenting manures were introduced into the 

 soil among the roots of grass, which was thus 

 made to grow more luxuriantly than that in 

 other places. The gases emanating from re- 

 torts containing similar manure were exa- 

 mined and found to consist chiefly of ammonia. 

 Sir Humphry considered such results as prov- 

 ing conclusively the advantage of applying 

 manures to soils in a recent and fermenting 

 state. (See AZOTE or NITROGEN.) 



Dr. Liebig's discovery of the great fertilizer 

 ammonia in rain-water has led to a most sim- 

 ple and beautiful explanation of the manner in 

 which gypsum or plaster of Paris acts in pro- 

 moting the growth of plants, a matter which 

 has been a subject of great speculation and 

 controversy, but which would seem to be fully 

 settled at last. 



"The evident influence of gypsum upon the 

 growth of grasses, the striking fertility and 

 luxuriance of a meadow upon which it is 

 strewed, depends only upon its fixing in the 

 soil the ammonia of the atmosphere, which 

 would otherwise be volatilized with the water 

 which evaporates. The carbonate of ammonia 

 contained in rain-water is decomposed by gyp- 

 sum, in precisely the same manner as in the 

 manufacture of sal-ammoniac. Soluble sul- 

 phate of ammonia and carbonate of lime are 

 formed; and this salt of ammonia possessing 

 no volatility is consequently retained in the 

 soil. All the gypsum gradually disappears, 

 but its action upon the carbonate of ammonia 

 continues as long as a trace of it exists. The 

 action of gypsum as well as that of chloride 

 of lime (bleaching salts) really consists in 

 their giving a fixed condition to the nitrogen, 

 or ammonia which is brought into the soil, and 

 which is indispensable to the nutrition of 

 plants. 



" Water is absolutely necessary to effect the 

 decomposition of the gypsum, on account of its 



