350 



THE FARMERS' REGISTER. 



amounts to only the 12,400ih part of its bulk, and 

 iodine is contained in salt water in the proportion 

 of one millionth. The air itself contains 79 per 

 cent, of tree azote, about 21 per cent, of oxygen, 

 and one-thousandth of cabonic acid ; but, unless 

 we provide azote lor plants in some other form 

 than that in which it exists in the atmosphere, ii 

 is useless. That lurm is ammonia; and in that 

 form we must look for ii in the air, as required for 

 plants. If we take a jar full of atmospheric air, 

 and look for ammonia in it, most of us will be 

 disappointed, the quantity exisis in so sn)all a 

 proportion. By recent calculations, Liebig found 

 that every cubic loot of air contains only a quarter 

 of a grain ol ammonia : Liebig has, however, 

 found It in the air. Ammonia is a highly volatile 

 substance, at an ordinary temperature exisiing 

 as a vapor ; but if that vapor comes in contact 

 with water, the water absorbs it so rapidly as al- 

 most to produce an explosion. Jjiebig conceived 

 the idea, thai il' we wisii to search for ammonia, 

 we must look for it in the water which falls li-om 

 the air, and by so doing has found it, as I have 

 done, by repea ing his experiments, Liebig took 

 100 gallons uf rain vifater ; he applied heat, and 

 distilled over four or five pints; he saturated il 

 with acid, so as to fix the ammonia ; evaporated it, 

 and it left crystallized muriate of ammonia. It 

 appears, however, that our air in Manchester is 

 Jich in ammonia ; for instead o." 100 gallons, we 

 had only to use 10 gallons ; and from the first 

 pint distilled, Mr. Neild and I succeeded in pro- 

 curing this quantity of ammonia [exhibiting a 

 .quantity crystallized in a glass]. It is natural to 

 expeci, where so much coal is burned, and where 

 there is so large an accumulation of human be- 

 ings, that if ammonia is to be found at all, it is in 

 Manchester, We see, therefore, that the atmo- 

 sphere will provide lor plants a quantity of am- 

 monia, and so small as is the quantity enterin<r 

 imo the composition of a plant, it is sufficient for 

 the developement of those principles which aie 

 requisite to the nutrition of the plant. If one 

 pound of rain waier contains only a quarter of a 

 grain of ammunia, then a field, having an area 

 of 14,000 square feet, must receive annually up- 

 wards ol SOlbs. of ammonia, dt 651bs. of nitro- 

 gen. This is much more nitiugen than is con- 

 tained in the form of albumen or gluten, in 2,650 

 lbs, of wood, in 2,y001bs. of liay, or in 200 cwt. 

 of beet-root, wliich are the usual products of that 

 surface. It also happens, that i he quantity f am- 

 monia thus brought down by rain, altera drought, 

 is larger than ordinary. In summer, a thunder 

 shower after a drought is very Lkely to bring 

 down, in the first part of the shower, a large 

 proportion of ammonia, Liebig look diffiirent 

 portions of strata of snow, and lound the larger 

 proportion of ammonia in the lowest stratum, 

 which of course tell first. The sensation of greater 

 hardness in rain water (felt on washing the hands) 

 than in distilled water, is owing to the quantity of 

 ammonia which rain water contains as compared 

 with distilled water. We have next to consider 

 how this ammonia appears in plants, or whether 

 it appears at all. Of this there is abundant evi- 

 dence presented in the evaporation of the juice 

 taken from the stem of the ma|)le tree, which is 

 generally saturated with lime, for the purpose of 

 throwing down the gluten it contains, and the 

 presence of the lime causes a disengagement of 



the gaseous ammonia sensible to all about. In 

 ihe manufactories of maple and beet root sugar, 

 this escape of ammonia is very strikingly expe- 

 rienced ; indeed this circumstance is one of very 

 serious loss to the beet-root sugar manufacturer; 

 for the ammonia given off, leaves behind it an 

 acid salt which prevents the sugar crystallizing, 

 and causes considerable loss by reducing the 

 sugar to a treacly state, in which only a portion, 

 instead of the whole, can crystallize. The pro- 

 ducts of ihe disiillation of flowers, herbs, and 

 roots, with waier, andall the extracts of plants 

 for medicinal purposes, contain ammonia. The 

 tobacco leaf coniains ammoniacal juice ; the juice 

 of the cut vine also gives oH' ammonia. In con- 

 nexion with iliese facts, we may allude to some 

 articles which the farmer employs to increase the 

 fertility of his land. Most of the composts used 

 are rich in nitrogen, particularly bone-dust, crush- 

 ed bones, and the shavings of horn, being parts 

 of dead animals; but there are also other sub- 

 stances, which, when thrown over the field, in- 

 crease lis fertility, simply because they combine 

 with the ammonia which comes down in raiu 

 water, and deprive it of its azote. Gypsum, or 

 the sulphate of lime, is extensively used, and, 

 when applied to a meadow exposed to alterna- 

 tions of wet and dry weather, causes it to pro- 

 duce abundantly ; but it IS lound not to answer 

 upon a dry meadow; and the reason is, that 

 when rain liiilis, if caibonale of ammonia exists 

 in the air, and comes into contact with gypsum, 

 it is converted into carbonate of lime, and the 

 ammonia is disengaged and absorbed into the 

 soil. The next stiuwer dissolves a portion of it, 

 which pusses down to the root of the plant, and 

 is assitnilaied by the plant itself^ Many soils con- 

 tain ammonia. If you take a piece of common 

 pipe-clay, and moisten it with a strong alkali, you 

 perceive at once a smell of ammonia given off 

 which will even continue lor a couple of days. 

 Oilier aluminous earths retain ammonia. Burned 

 clay is often used by farmers to apply to their 

 land ; and burned clay is now lound to absorb and 

 retain ammonia. The ferruginous earths (those 

 which contain an oxide of iron) also retain am- 

 monia ; and one of the most solid of these oxides, 

 the hematite, or red oxide of iron, a stone, contains 

 one per cent, of this gaseous principle. It is from 

 these facts — now for the first time explained by 

 Liebig — that the materials used by the farmers 

 prove beneficial in their application to ll;ie land. 

 //w?mis is a spongy body, which absorbs ammo- 

 niacal gas to a considerable exient; and, with 

 every shower of rain, it gives it out to be taken 

 up by the roots of the plants. Plants, then, 

 derive their nourishment fi'om carbonic acid, am- 

 monia, and water; these being the principal 

 sources fiom which plants derive the greatest 

 part ol their bulk and weight. The plan assimi- 

 lates to itself these respective elements from car- 

 bonic acid, ammonia, and water. In the decay 

 of plants, these elements float to other plants, are 

 again assimilated by them, and thus the destruc- 

 tion of one generation of plants furnishes the 

 materials out of which another is to be formed. 

 The intermediate processes are obscure ; but still 

 lights are to be thrown upon them, by analogy, 

 which may form the subject of another com- 

 munication. Let us now consider what other 

 materials we find in plants. If a plant consisted 



