1S37] 



F A R M E R S' REGISTER. 



273 



fTetahle matter, totrether with frecjiieiit stiniriir or 

 uilitation ol' any kind, retards, and sometimes al- 

 toijeiluT prevents, the change whicli would under 

 o|)posi!e circumslances gratiually ensue. So long 

 as humin is lve|)t Irom contact with the air, it con- 

 tinues insoluble and antiseptic. It is consequently 

 almost indeslructihle when situated a lew feet he- 

 low tlie surface ol' the ground, and at that depth 

 is not only found, as in the inslance of church- 

 yards, in large qiuuitiiies, hut may also be retain- 

 ed uuimpau-ed for an unlimited period. In such 

 situations, too, it cannot undergo certain changes 

 necessary to ensure, its soluliilil}', and it is there- 

 fore inert, ami totally unfit for the purposes of ve- 

 getation. No sooner, however, is it brought by 

 the plough ors|)ade to the surface of"lhe earth, than 

 ii begins to alter. Pari of its carbon, uniting with 

 the oxyijen of the atinos|)here, lorms carbonic 

 acid, which is readily absorbed by the green parts 

 ol plants ; while its hydrogen, combining with 

 another portion of oxyueu, produces water. "Tiie 

 residue becomes a soluble extract, and in that state 

 is taken up readily by the fibres of the roots. But 

 the changes still >ro on ; the extract absoibs more 

 oxygen, and becomes once more insoluble in the 

 fiirm of a film, whicfi Fourcroy (;alls vegetable al- 

 bumen, and which contains a small portion of ni- 

 trogen readily accounted for. By tiringiug fresh 

 portions of humii"! to the surface, and perniitting 

 the access of air to it, more carbonic acid, water, 

 extract, and albumen are formed, and ffive a reg- 

 ular supply lo the plants. * * Hence we see the 

 threat imporiauce of Irequenlly stirring the surfiice 

 of ihe earih." * * — (Penny Cyclopaedia, article 

 Arable, which contains an excellent condensation 

 of the views of Thaer, of Berlin, and Theodore 

 de Saussure, of Paris.) 



This compound of humin and oxyiien (humic 

 acid) readily combines wi;h many of' ihe earthy 

 and saline substances found in manures, and ren- 

 ders them of easy solubility in water. Hwinates 

 (as they are termed by chemists) of lime and 

 potass are in tliis way formed in the soil and, 

 fi'om the liicility with which they are dissolved in 

 water, gain a ready access to the interior of plants. 

 Ol" this action the old wriiers were completely ig- 

 norant, and thereft)re puzzled themselves to no 

 purpose in endeavoring to account for the presence 

 of so insoluble a body as lime, in any quantity, in 

 plants. They had, however, a glimpse of the 

 truth, as we cannot identify the substances which 

 they so vatjuely treat of under ihe names of vege- 

 iahle extract, extractive, and inucilaginous matter, 

 as exactly similar to hvnini and humic acid, so 

 ably described by the modern chemists of France 

 and Germany. 



The imporiance of humin to a soil, or rather to 

 the plants which it supports, can hardly be over- 

 rated. It is the chief supporter of vegetation, as 

 well as an indis[)erisable solvent of several earths 

 and salts fi-om which plants derive much aid in 

 the progress of their growth. Its mechanical ac- 

 tion on a soil is also of considerable moment, serv- 

 ing, as it does, two extremely opposite purposes, 

 that of biniling together and consolidatina; loose 

 sands, and that of breaking up and rendering po- 

 rous stiff" clays. The effects produced in this way 

 by rich manures, capable of affording a large 

 supply of humin, are superior to those resulting 

 from the application of any of the other repaireis 

 of a soil. It secures, too, when present in any 



Vol. v-35 ' ' 1 y 



I quantity, a constant supply of moisture lo the 

 earth ; and as the ciiemical action detailed above, 

 by which the water is [)roduced, alwaj's goes on 

 wilh increased rapidity in warm weatlier, it Ibllowa 

 that richly manured lands are almost safe from 

 the bad effects of long-continued drought. Too 

 great a quantity of water is, on the other hand, 

 highly detrimental to ground containing much hu- 

 min, or organic matter Horn which it can be formed, 

 as lermenlalion is encouraged, and a compound of 

 an acid and astringent nature produced, which is 

 exceedingly injurious to vegetation. Moss, [peal] 

 for example, is a kind of soil in whicli this process is 

 constantly prouressinu-. Hence the correct popu- 

 lar opinion that such land is sour, and hence the 

 equally correct and wel! known mode of removin;^ 

 the astringency by draining the land and neutrali- 

 zinir it with lime. 



From the (London) Fanners' MagaziiiP, for June, IS3T. 



POINTS ly CHKiMISTUY APPLIED TO AGRICUL- 

 TURE. — SOILS. 



No. 2. 



Those who undertake to investigate the rela- 

 tions of plants to soils, are embarrassed by pecu- 

 liar difficulties. They are entering upon a field, 

 the range and boundaries of which are unknown 

 to them, because the confines are, as yet, unpas- 

 sed: they are groping lor deductions, ff-oni obser- 

 vations that are as variable and uncertain as the 

 occurrences to which they relate, and which the 

 fi'amers of these remarks would have us to regard 

 as regular and fixed. A store ol" /acts, collected 

 from every quarter of the world, has yet to be 

 amassed. Here and there, doubtless, an inciden- 

 tal observation of considerable value is to be found 

 in the records of our agriculturists and travellers, 

 which is serving as a kernel, round which other 

 fragments will be gathered; but much straggling 

 infi)rmation has still to be contributed, and much 

 careful reasoning has yet to be expended upon it, 

 and devoted to its arrangement, before these iso 

 laled oc^-urrences can be connected and consoli- 

 dated, so as to serve the important purposes which 

 have been assigned to this species of knowledge, 

 and meet the sanguine expectations which men of 

 talent have, doubtless, been correct in forming re- 

 garding it. "In lact," says Mr. Macgillivray, ^'be- 

 fore any such results could be attained, we should 

 require for data, accurate and perspicuous accounts 

 of all the different countries and climates of the 

 world, viewed with reference to their soils and 

 plants. But of such data do we yet possess even 

 one. The botanist has gone forth by himself", and 

 discovered the veiretation of an unknown region; 

 the geologist has followed in his steps, but he has 

 noted the rocks, and their mutual relations only. 

 None has yet been able to look upon nature with 

 an eye capable of seizing all her ligatures. Hum- 

 boldt may perhaps be said to have made the at- 

 tempt, but many Humboldts must run their ca- 

 reer before the complicated organization of" mun- 

 dane nature can begin to become intelligible." 



Few things would appear, at first sight, easier 

 to be judged of, than the value of a soil, as evi- 

 denced by the vegetation on its surface. A parti- 

 cular combination of earths might be supposed to 

 be capable of producing only certain plants, and 



