46 



1851.1 



THE AGRICULTURAL GAZETTE. 



/ 



33 





rZ^fr the operation of the ordinary laws of chemical 



The adhesive attraction which produces the former 

 j these remarkable effects, although exerted in different 

 imoftl for different salts, seems to be exhibited more 

 ^C§ for all. Thus, water containing common salt, if 



to filter through clay, loses a portion of its 



in the light of a prolongation of the plant which 

 supports it, in the same sense, at least, as a new ahoot is 

 of the original trunk, or a scion of its stock. When 



according to the 



*Je to niter uiu-ugu «■*/) »«w» *% pvinvn ui no 

 Lfce impregnation. But the decomposing agency of 

 JkTsoil is evinced principally with reference to salts of 

 l^amonia which are often made to exchange their acids 



th those combined with other bases brought into 

 antact with them, such as lime and magnesia. 



Accordingly, sulphate and muriate of ammonia will be 

 converted into the carbonate in their passage through 

 ekr and the latter, through the adhesive affinity exerted 

 for it by the earth, will be detained within its substance. 

 Hence water holding sulphate or muriate of ammonia 

 in solution, if made to percolate a certain thickness of 

 rentable mould, containing some proportion of argilla- 

 ceous earth, will come out entirely free from all ammo- 

 niacal salts, but containing, in the place of it, either sul- 

 phate of lime, or sulphate of magnesiaj 

 nature of the earth present in the soil. 



For the same reason it is that sewage- water may be 

 freed from all its impurities, by being made to filter 

 through a certain thickness of clay. 



It is needless for me to remark upon the important aid 

 this discovery affords us towards preserving and concen- 

 trating the valuable contents of our manure-heaps. We 

 see thatan admixture of clay or marl in sufficient quantity 

 with decomposing animal and vegetable exuvise, will pre- 

 vent the escape of ammonia, and even of alkaline and 

 phosphatic salts, although the water which contained 

 them be allowed to drain off, after passing through this 



material. 

 We perceive, also, under what circumstances it may 



be admissible to employ as manures such salts of ammo- 

 nia as, when alone, would be useless in vegetation, because 

 the plant being unable to separate from them their alkaline 

 ingredient, could not obtain from them any nitrogen ; 

 and we also see opening upon us a promising train of 

 research, which may not improbably suggest to us here- 

 after the means of availing ourselves, for the purposes 

 of husbandr/, through the instrumentality of certain 

 mineral substances, of the whole of that immense accu- 

 mulation of faecal matters which is now emptied into 

 the Thames, and at the same time of disarming it of its 



destitute of them, it implants its roots iato the bark, in ings, although unfitted for the 





noxious influences upon mankind. 



But I must hasten on to a few other examples of the 

 service rendered by chemistry to husbandry, and I 

 know of scarcely any to which I can appeal with greater 

 confidence than to Professor Liebig' s refutation of the 

 humus theory of vegetation, and of his exposition of 

 the true manner in which plants obtain their nourish- 

 ment from the soil. 



I am aware that Mulder * and a few others still pro- 

 fess to adhere to the old opinion, that humus does 

 actually supply nourishment to plants, by being rendered 

 soluble in the sap, and taken up along with it into 

 their tissues ; although the Dutch chemist himself 



seems to leave the 



doubt 



another 



question in uouDt in 

 place, where he states, that it is still open to investiga- 

 tion, when humus, as such, appears to have nourished a 

 plant, whether it had not been previously decomposed 

 into carbonic acid, and in this state had supplied 

 nourishment to the roots. 



On the other hand, on reviewing the arguments which 

 incline him to the belief that humic acid is actually 

 taken up into the vessels of the plant ; whilst on the one 

 h&nd I see no reason to deny the possibility that its 

 soluble salts may occasionally be contained in the sap, 

 as is the case with other saline solutions brought into 

 contact with the roots, I can, on the other, discover no 

 proof that such is by any means an ordinary occurrence, 

 <* one having any reference to the nutrition of the 

 vegetable. On the contrary, the sap of plants, whenever 

 it has been examined, is found to consist of the same 

 "igredients, namely of water, carbonic acid, carbonate 

 of ammonia, and saccharine matter ; but never to con- 

 kin humus under any of its modifications. 



Now the onus probandi surely rests with those who 

 Maintain a theory so opposed to all analogy, as that of 

 Apposing the vegetable to be nourished, in any degree, 

 ^ means of a material, which is, at any rate, wholly 

 adequate to supply any considerable portion of what is 

 necessary for its growth ; as has been demonstrated both 

 ty Liebig and by Schleiden, authorities who, differing 

 w they do on many other points, agree at least in this one. 



Nature, however prodigal she may be in results, is 

 chary as to the means she employs to obtain them ; she 

 ■j? 8 no occasion to resort to expedients to which man is 

 often driven, who, having begun his work with one set 

 of instruments, is induced to perfect it by the aid of 

 pother ; and in this case physiologists have shown, that 

 *" e has provided an entirely distinct machinery for the 

 purpose of accomplishing the assimilation of the four 

 ^ganie elements, namely the specific influence of the 

 luminous rays upon the green parts of the vegetable 

 hssue, by which carbonic acid, water, and probably 

 •tonxoaia, are decomposed; and carbon, hydrogen, oxygen, 

 *tf nitrogen, assimilated.f 



*he absorption of sap by parasites from the parent 

 . irc ^ which Mulder appeals to in support of his theory, 

 ? bv no means a parallel case to the absorption of 

 ^us by the roots. The forme* can only be regarded 



the highest place amongst the qualifications n< led for 

 success. 



But with all these deductions, it may be safely 

 serted, that there is scarcely any process in the art of 

 culture, however entirely it may have originated with 

 unscientific men, which would not be benefited, by being 

 brought so far under the domain of chemistry as to be 

 carried on with a constant reference to its principl 



1 



You must have seen, in the course of my *r< vioug 



tures, abundant proof of this, in the remarks that have 

 from time to time been made, on the management of 

 farm-yard manure, on the ««tion of artificial suhtt) 

 tutes for it, on the u*et of ullage, and on the methods of 

 rendering the soil available for the nourishment of 

 plants r can there be any doubt, that in pr portion 



as our scientific knowledge advances, in proportion as 

 agricultural chemistry is cleared from those doubts 

 which hang over some of its principles, and also in 

 proportion as the Jtn< ralisations deduced from its facta 

 by the first authorities be< ic rooted in the minds of 

 practical cultivators, it will, as Mr. I'tiney ant pates, 

 bring forth more fruit, and vindicate more completely 

 than at pressnt its elai to an important, although 

 always, no doubt, a subordinate place, amongst th 

 ([iiirements of the practical agriculturist 



Home Correspondence. 



Pent Charcoal. — I shall 



of your 



philosophers, who had made physics the principal busi 



nest of their lives— instead of continuing, as it has 



hither: lone, to supply an healthful and improving- 



supplied with leaves, the parasite elaborates its own sap occupation to that larger body of practical and intelligent 



receiving the crude material from the new wood ; when j persons, whose plainer and less cultivated understand- 



_ w . w abstractions of science, 



order to obtain the sap already elaborated ; but in I are perfectly competent to grapple with the difficulties 

 either case the mode of nutrition is entirely in harmony | of an art, in which it seems intended, that tact, and 

 with that of plants in general, and can in no degree be j sagacity, and experience should, after all, alwavs hold 



appealed to, as countenancing the anomalous theory - 1 ' JL - - 1 k -• •— • ■ - - 



which supposes humus itself to be taken up and assi- 

 milated. 



Although, therefore, much that relates to the nutri- 

 tion of plants may be still obscure, I cannot admit that 

 this is the case with respect to the manner in which the 

 materials present in the soil are rendered available ; 

 conceiving, as I do, that the doctrine maintained by 

 Liebig, even though it may still be doubted by a few, 

 commands the assent of the scientific world generally 

 enough, to be considered a safe foundation for practice. 



Assuming, then, that the humus theory, which sup- 

 poses vegetable mould to constitute in itself the food of 

 plants, has given place to the doctrine which repr. nts 

 it as serviceable only, in proportion as it supplies, through 

 its decomposition, or its absorbent properties, carbonic 

 acid and ammonia; I will beg you to consider how much 



light has been thrown upon the hidden operations of 

 agriculture by the establishment of such a truth — how 

 greatly, on the one hand, our practice may be modified, 

 and our methods of culture improved, by having the 

 principle impressed upon our minds, that humus must 

 undergo a kind of decomposition, before its constituents 

 can become assimilated — and, on the other hand, how 

 many faulty proceedings may be discontinued, through 

 the rejection of the crude notion formerly in vogue, that 

 plants are nourished in the soil on which they grow, in 

 the same sense, and by the same process of assimilation, 

 as animals are by the plants on which they feed. 



The above examples may suffice to show the benefits 

 which science has conferred upon agriculture, properly 

 so called. 



There is, however, another branch of rural economy, 

 namely, the art of feeding and fattening domestic 

 animals, in which the services rendered by it are 

 even more palpable, and less open to dispute. To 

 know that warmth is to a certain extent a substi- 

 tute for food ; that every expenditure of muscular force, 

 and even every exertion of mental or bodily power, 

 involves the consumption of an equivalent amount of 

 animal tissue — that sugar, gum, and starch, no less 

 than oil, are convertible by the processes of the animal 

 economy into fat — a principle which even Dumas is at 

 length compelled to concede ; that the temperature of 

 the body may be maintained by means of a cheaper 

 kind of nourishment than is needed for supplying the 

 waste of the system ; are facts which cannot but prove 

 of the highest practical utility to all those whose business it 

 is to provide animal food for the wants of our population 



On these topics, however, less need be said, because 

 ample justice has been done by Mr. Pusey, in his valu- 

 able report, to the services rendered by Baron Liebig 

 to this branch of our subject. 



In conclusion, then, let me request you to "consider, 

 whether the facts that have been brought forward 

 in the course of this Lecture do not hold out 

 inducements to all those engaged in agriculture, 

 whose time and education permit, for making them- 

 selves familiar with the first great truths of chemis- 

 try, and for keeping its principles steadily in view in all 

 the operations of farming, and especially whenever they 

 aspire to innovate and improve upon existing methods. 

 It may be true, that some of the principles alluded to 

 were suggested at a period antecedent to that included 

 within Mr. Pusey 's Report. It may also be true, that 

 the germ of some of the most important facts or generali- 

 sations announced to us by Baron Liebig, is traceable to 

 Saussure and other of the earlier experimentalists. 



These, however, are points which, however much they 

 may concern the reputation of the individuals, cannot 

 affect our judgment as to the utility of science itself, or 



be obliged by any 

 correspondents informing me of their experience with 

 peat charcoal, in growing Potatoes or Turnips. A, 

 friend of mine, who was at considerable pains and 

 ex | '"Me in preparing some, tried it this season upon 

 both ; but without t slightest apparent Wnefit. The 

 Potatoes, upon which a good allowance of charcoal wtf| 

 put, over the sets and dung, at planting me, weri 

 neither a better crop, nor freer of disease, than the rest 

 of the field. Upon Turnips, three drills were manured 

 only with charcoal, saturated with \mne 9 from a feeding 

 shed — the rest of the field has a good crop, but upon 

 these three drills the Turnips arc few in number, and 

 are not larger than Radishes. Tried upon Grass, on 

 lawn, it has not been more successful. If this much be- 

 praised deodoriser (fertiliser we cannot call it) is not 

 found to answer better elsewhere, the bogs of Ireland 

 are not likely to turn out quite the California some 

 patriots (speculators I) would have us believe. 1 have 

 a fair crop of Turnips, upon a thin gravelly soil, 

 would be much improved were the crop eaten off by 

 sheep, folded upon the field ; but this is not convenient. 

 I am told that the soil will; be equally benefited by 

 leaving the tops of the entire crop to rot on the sur- 

 face ; or rather ought 1 to plough them in whilst 

 green? [Plough them in green.] The Potato crop 

 in this county (Dumfries) is generally light ; the 

 disease varying according to quality of soil, whilst 

 light, dry, gravelly, or pure mossy soils have not more 

 than one-sixth -or one-eighth ; heavy loams and damp 



eased 



w h i ch 



clays have as much as one-half and two-thirds di 

 tubers. Upon some high lying farms the stems wens 

 blackened by frost in the beginning of July ; here the 

 tubers are few and small -not half a crop. Oats will 

 be a fair average. In high, damn localities much of the 

 crop, though cut three weeks since, is still in the fields ; 

 and, from the late wet and warm weather, must now 1* 

 injured by sprouting : a great deal, too, destroyed by 

 rooks, wild pigeons, black cocks, and grouse— the last as 

 destructive as any ; and then they come in such numbers 

 vou can hardly drive them away— to use a gun would 

 be high treason ; a human you may shoot, when carry- 

 ing off your property, but with a black cock or grouse, 

 it is quite " un autre cho$c" They manage these 



w v . matters better in France now, at any rate. A word 



as to the probability of further assistance being derivable I ^ Q9e curm i n g ro gues, the rooks; all summer 



. *f_ vt :n t Aim**- *u» n*-5ftn« j have had a i^y to keep them from a 6-acre field of 





Chemistry of Vegetable Physiology," chaps, v. and viii. 

 jjj*_? e ? L-iebig'g " Chemistry in its application to Agriculture," 

 tttjq Ui ' 1 *** Scaleiden's " Botany, Engl. Trans." p. 473, 





from its prosecution. Nor will I dispute the position, 

 that, with the exception of the addition of sulphuric acid 

 to bones, and the employment of flax-water as a manure, 

 no successful process of recent introduction can be ap- 

 pealed to, solely and distinctly referable to the sugges- 

 tions of the chemist ; * and still less would I seek to en- 

 courage amongst my hearers the notion, that for every 

 agricultural difficulty a chemical nostrum can be devised. 

 It would be as absurd for a mere chemist to conduct a 

 farm, as for a mere mathematician to command an 

 army ; although the best arrangement of troops in a 

 battle may be a mechanical problem, and an Archimedes 

 may have done good service to his countrymen, by firirg 

 the enemy's fleet, through the resources of science. 



If, indeed, success in agriculture were so dependant 

 upon the manipulations of science, as some sanguine 

 persons, to whom Mr. Pusey's remarks are addressed, 

 appear to have imagined, the consequences would b 

 much to be deplored'; as it would transfer the cultiva- 

 tion of our fields to the charge of a comparatively small 

 number of men erf subtle an djrefinedjntellects— closet 



• May not, however, the uieof char %\ in borticaUarf sug- 

 gested by its absorbent Dowers with reference to g%*es, be neia 

 as another boon conferred by chfmiat ; and the power of 

 gypsum in fixing amm ia— the failure in the use of winch i-, 

 I beli ve f mainly attributable to the mineral not hsTinjr De« 



exposed to heat before ic was pulverised, «" fi b*»»ff i PP ,w i(l 

 a dry *tate, instead of ben mixed up With water to the con 



STStente of ctearn — be cited as another! 



Potatoes. On Sunday week the callant went home to 

 bis mother's for a clean shirt. The crows soon ob- 

 served, and took advantage of his absence ; for some 

 three hours tl J bad it all their own way, and so good 

 a use did they 'make of their time, that next morning 

 11 half-bushel basketsful of half-eaten Potatoes were 

 gathered off the drills ; how many were wholly eaten,, 

 and how many were carried away, could of course only 

 be guessed at. As there is no unmixed good in this 

 world, so neither is there any unmixed evil— the crows, 

 though they occasionally help themselves rather more 

 liberally than we like, to the corn and Potatoes ia 

 autumn, do good service at other seasons of the j ear by 

 destroying myriads of slugs, grubs, and other small 

 deer," which, though unseen, are not the less active m 

 blighting the hopes of the Tenant Farmer. 



Beer.— In reply to « Senex," in your Number of the 

 25th, I beg to inform him that an ale far superior to 

 Bass's (I speak medically and gastrononucally) can be 

 easily brewed from sugar and hops ; and as the quality 

 of sugar is less variable than that of malt, with more 

 certainty of success, according t<> the recipe given by 

 lichael Donovan in his w Jv-mesttc Economy, pub. 

 Hshed in Lardner's " rSwlepn a." This work is valu. 



able in many respects 



Cyclop 



but especially in its exposure of 



impositions "practised to profit - the few at the expose 



