410 



NEW ENGLAND FARMER, 



JUNE 8g, 1843. 



CHEMISTRY OF AGRICULTURK. 



The following interostins and valuable paper 

 was read before the late Convention of Geologists 

 at Albany : 



Dr. C. T. Jackson road a report on the organic 

 matters of soils, and exhibited specimens of them 

 and their characteristic salts and compounds. He 

 demonstrated the complex nature of mould or Hu- 

 mus, and proved that only refined and exact analy- 

 ses would show the causes of fertility and barren- 

 ness in soils. Several cases in point were cited, 

 and among others the analysis of three soils ; one 

 of which was almost barren ; the second was mo- 

 derately fertile ; while the third was remarkably 

 productive and had been cultivated fjr nearly one 

 hundred years. In these three soils the relative 

 proportions of organic and mineral matters were 

 precisely the same, insomuch that it was supposed 

 at first that they were all taken from the same 

 spot; but a more refined analysis showed a very 

 marked difleronce in the condition of the organic 

 matters, and to this difference, imperceptible to an 

 ordinary or crude analysis, the difference in fertili- 

 ty was owing. 



The organic matters formerly confounded under 

 the names of Ulniin, Geiue and Humus, are nu- 

 merous and very different in their chemical na- 

 ture, varying in different soils and producing va- 

 .rious degrees of fertility. 



Berzelius who first described and named Goine, 

 ■has utterly abandoned that name as improper, 

 there being no such proximate principle, it having 

 been proved to be a very complex compound of 

 new and peculiar acids. Those which we know 

 at present are the following: Urenic acid, Apo- 

 crenic acid, Humic acid, Humin, Extract of Hu- 

 mus, Glairin, Glucic acid, Apoglucic acid and 

 Coal of Humus. The five first of these substan- 

 ces are generally present in fertile soils. Crenic 

 acid forms two salts with lime, one of which, the 

 Crenate, is very soluble in water and in alcohol, 

 while the sub-Crenate is more difficultly soluble. 



Apocrenic acid is highly charged with Nitro- 

 gen, and is a very valuable ingredient in soils, 

 furnishing a portion of the nitrogenous matter of 

 plants. It is probably formed by the gradual 

 change of vegetable matters through the influence 

 of the air and anomical salts derived from decom- 

 posing animal manures and from rain. It forms 

 from the Crenates and Humates ivhen they are ex- 

 posed to atmospheric influeneo, by breaking up the 

 soil during cultivation. Hence we see that a yel- 

 low soil turns black by two or throe years expos- 

 ure to the atmosphere, and from an unfertile state 

 becomes fertile. We can readily produce the 

 same result in a few hours, when we operate on a 

 small quantity of soil in the Laboratory. Apocre- 

 nic acid forms salts with lime and with peroxide of 

 Iron, which are nearly insoluble ii,! wjler, but 

 which are readily decomposed by the action of 

 Carbonate of Ammonia, or by potash or soda ; so 

 that we may readily conceive of the fertilizing in- 

 fluence of these alkaline matters, since they ren- 

 der the organic manures, which were before inso- 

 luble, perfectly soluble in water, so that they may 

 be absorbed by the rootlets of plants. If these 

 matters are absorbed, as they infallibly must be, it 

 is evident that they must undergo a series of modi- 

 fications in the sap vessels, so that they are no 

 longer found in the juices of plants in the state 

 which they were when they were first absorbed. 

 Now, by analysis of the sap of plants before the 

 putting forth of their foliage, we find certain ex- 



tractive matters and sugar. In some, Apoglucic 

 and Glucic acid have been discovered. 



Let us then nmsider the composition of these 

 substances, and see whether it is possible for Hu- 

 mic acid, for instance, to pass, by chemical changes, 

 into Sugar. 



Carbon. Hydrogen. Oxygen. 

 Sugar is composed of . . fi 10 5 



Glucic acid of 8 10 5 



Humic acid of 40 24 12 



Ulniin from sugar .... 40 32 14 



Now 11 atoms of Sugar consists of 06 carbon, 

 110 hydrogen, 55 oxygen, and may form, by de- 

 composition according to Multer, 



Carbon. Hydrogen. Oxygen. 



3 atoms of glucic acid 24 30 15 



1 " ulmin....40 33 14 



I " formic acid 2 2 3 



23 " water 46 23 



66 110 55 



Then by the opposite action, which is the rege- 

 neration of vegetable matter, we may have ulmin 

 or humic acid converted into glucic acid, formic 

 acid or sugar. Now since this action takes place 

 in trees anterior to the development of the foliage, 

 the organic matter operated upon may be derived 

 from the soil. 



By the action of the atmosphere, glucic acid is 

 converted into apoglucic acid, and by the action of 

 nitrogenized bodies it is further converted into 

 crenic acid and apocrenic acid. Thus we see how 

 these important organic matters may be formed 

 from ordinary vegetable matter, by exposure to the 

 influence of moisture, atmospheric air, and the 

 soil. 



Dumas regards vegetables as true organs of re- 

 duction or do-oxidation, while animals are regard- 

 ed as organs of combustion or oxidation. Thus 

 while plants absorb carbonic acid and give out 

 oxygen, animals absorb oxygen and give out car- 

 bonic acid gas. Plants directly or indirectly fur- 

 nish us with our aliment, and after consuming it, 

 animals render the same amount of matter to the 

 vegetable kingdom in another form, which is better 

 adapted to their use. Thus we see the great and 

 mysterious circle of the revolution of organic ele- 

 ments is complete. 



Besides the organic matters derived ftom vege- 

 table mould, we must consider the action of sa- 

 line matters which constitute the necessary com- 

 ponents of plants. 



We have already seen by the beautiful research- 

 es of Prof. Baily, that nearly all kinds of forest 

 trees contain in their bark, and enclosed in their 

 sap vessels crystals of oxalate of lime, more than a 

 million of which Jiave been discovered in a square 

 inch of the bark of the birch tree. This discovery 

 is truly interesting, for it shows us another step in 

 the process of changes of organic matter ; for it is 

 one of the easiest things for the chemist to con- 

 vert sugar into oxalic acid. We must not fail to 

 remark also that while oxalic acid is a deadly 

 poison, that oxalate of lime is perfectly harmless ; 

 so that here we have this powerful acid in chains. 

 What function this salt performs in vegetation is 

 yet unknown. 



When we examine any kind of grain or any 

 seed which is not charged with oil so aa to pre- 

 vent an examination by the lest we shall now de- 

 scribe, it is discovered that the seeds contain phos- 

 phates of certain bases. During the spring of 

 1840, Dr. J. discovered the presence of phosphoric 



acid in Indian corn, wheat, oats, beans, peas ant 

 chesnuts. This was done by burning away the 

 seeds by heat and nitric acid, when in several 

 cases glacial phosphoric acid and phosphates ot 

 lime and magnesia wore discovered. In his first 

 operations the whole seed was burnt in order to ob 

 tain the ashes for analysis, but having been shown 

 by Mr. A. A. Hayes specimens of Indian corn 

 which were soaked in a weak solution of sulphate 

 of copper, whereby the precise limits of the phos- 

 phates were shown by the formation of phosphates 

 of copper, he was induced to examine the situation 

 of these matters by this test; and then by dis- 

 secting out the organs of the plant which contained 

 the phosphates, he was enabled to analyze them in 

 a more thorough manner so as to arrive at inter- 

 esting and important results. 



Specimens of various seeds were exhibited to 

 the Association, which demonstrated the presence 

 of phosphates in the Cotyledons only. This was 

 stated to be a general fact in every case where the 

 experiment had been tried. The presence of the 

 salts above noticed is a most important discovery. 

 It explain? the origin of the bones of animals. 



Around the cotyledon of Indian corn, Mr. 

 Hayes discovered a layer of a salt of peroxide of 

 iron. This was also demonstrated by examples 

 shown to the Association. This iron shield around 

 the cotyledon of corn is not to be overlooked, for 

 it is the source of the oxide of iron which enters 

 into the composition of the red globules of the 

 blood of animals. 



Indian corn also contains a fat oil which exists 

 in the transparent hard portion of the corn, com- 

 bined with starch and a peculiar nitrogenized body 

 called Zeine. This serves to form the fat of ani- 

 mals, and the starch and zeine form the carbona- 

 ceous compounds of the muscles and tissues. 

 What an interesting subject for reflection is a 

 grain of corn ! 



In order to advance agriculture, the best ser- 

 vices of the chemist are required. Rude analyses, 

 such as are recommended by most of the news- 

 papers and popular books on agriculture, serve 

 only to retard the progress of this most important 

 of human arts, and to degrade it in the eyes of the 

 people, and it must be kept in view that no analy- 

 sis containing an error of two per cent in the min- 

 eral constituents or one Jive hundredth per cent in 

 the organic matters and salts, will show the differ- 

 ence between utter barrenness and the richest fer- 

 tiliry. 



The results arrived at by the researches of che- 

 mists may be thus briefly summed up: — 



Plants derive their nourishment from air, water, 

 and from the soil. 



The principles which they absorb are taken up 

 in a gaseous or in a liquid state, and are absorbed 

 part by the foliage and partly by the rootlets. 



The matters taken from the air are carbonic 

 acid gas, oxygen, and perhaps a portion of nitro- 

 gen. 



The carbonic acid is decomposed by the com- 

 bined action of the foliage and sun-light ; carbon 

 is retained in the plant, and oxygen is eliminated 

 and exhaled. 



During the germination of seeds, and during the 

 ripening of fruits, oxygen is absorbed. 



It is probable that nitrogen enters into plants 

 only ill solution in water or in combination with 

 hydrogen, ammonia, or with the organic acids, 

 which have been described in the former part of 

 this report. 



