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the reft oftlie tree, as it pofTcfTtd the red colour of the wood 

 of the! phini-trco, from \.vi»ich the bark haj been removed. 

 The otlier experiment is equally decifivc; lie palfed Icyeral 

 filver wires through the bark of a tree, in the feafon of full 

 vegetation, fonic of the wires only went through the paren- 

 chyma, whilll others were inferted into the liber; thofe 

 which liad only penetrated the cellular tiffue, obeyed the 

 excenlric progrefs of the baik, and as the tree grew came 

 nearer the furface; but the wires which had palTed through 

 the liber, were carried towards the centre, and after fome 

 years, were found covered with many layers of wood. 



The conchilion which Du Hamel drew from thefe expe- 

 riments was, that the bark produced the liber, t!ie alburnum, 

 and the wood; but it is Mirbcl's opinion, that the wood in 

 giving origin to the cambium, produces tlie liber, which is 

 finally converted into both the bark and wood. For the 

 further difcuffion of this fubjeft, fee Cambium, Liber, 

 and Wood. 



It fliould be obferved, that the period of vegetable exift- 

 cnce depends upon the power of the plant to produce tlie 

 cambium, and confequently, the liber; accordingly, in herbs, 

 riiofl of which do not furvive one or two years, the fuc- 

 ceffive layers which charafterife the wood of trees, are not to 

 feen. 



Hitherto we have been defcribing the arrangement of the 

 cortical layers, iu the Dicotyledons ; in tliofe plants, how- 

 ever, whicli are called monocotyledons, or having one fcminal 

 Itaf, the difpofition of thefe parts is very different; only the 

 cuticle and cellular fubllance are found on the iurtaee of 

 thefe vegetables; there are no concentric layers of either bark 

 or wood; the interior of the plant is filled with parenchyma, 

 in which are contained the woody fibres, fcattered at irregu- 

 lar diftances ; the cambium is depofited round each fibre, and 

 there produces the tubular and cellular tifTue ; the tubular 

 tiffue forms firft the porous wood or alburnum, which con- 

 tracls in thicknefs, elongates and is infenfibly converted 

 into the perfe£l wood, and in contrafting is detached 

 from the parenchyma and leaves a vacancy which is pre- 

 fently filled up by a new cambium ; each of thefe fibres, 

 therefore, might with propriety be confidered as a dif- 

 tincl vegetab'e, inafmuch as it has the means of an inde- 

 pendent growth. See Cambium, Wood, Monocotyledon, 

 and Dicotyledon. It has already been obfened, that fome 

 of the more fimply organized vegetables, fuch as the fungi and 

 fuci, do not poffcfs in any of their iubilance either cortical or 

 woody fibre3,but are altogether compofedofthecellular tiffue. 



After the account which we have given of the different 

 parts entering into the ilrufture of the bark, it is unnecef- 

 fary to intilt upon its ufes in the vegetable fyflem; in it re- 

 fide almoft all the powers and energies of the plant ; wounds 

 only are healed by it ; upon the exatl contaft of the libers 

 of two trees depends the whole of the fuccefs in engraft- 

 ing; and in the bark are prepared n;it only all the juices and 

 fecrctions which are required for the fullenance andincreafe 

 of the plant, but thofe pecuHar fubllances which are appli- 

 cable to fo many of the purpofes of common hfe and of me- 

 dicine. See Vessels, Succa Propria, and Secretion. 



Bark, Peruvian, Cortex Peruvianus. The high import- 

 ance in medicine of the peruvian bark has appropriated to it 

 cxclufively the term of the bark. We fliall dcfcribe it under 

 the botanical and now officinal name of Cinchona. 



Bark, in jigriculture, a fubftance frequently employed 

 by cultivators as a manure to particular kinds of land. 



The bark of trees in general, and particularly that of the 

 oak, becomes an ufeful manure after it has been employed 

 by the tanner in the preparation of leather. One Joad of 

 oak bark laid in a heap and rotted after having been thus 



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ufcd, it is faid, will do more fervice to ftifT cold land, and it» 

 effects will la;l lo-gcr, than two loads of the richclk dung, 

 Mr. Miller in his Dictionary obferves, tliat it is much better 

 for cold flrong land than for light hot ground, it it be ufcd 

 alone as taken from the tan-yard ; bvcaufe it is of a warn\ 

 r.atnrc, and it will loofen and feparate the earth fo effeflually, 

 that, by only employing it two or three times, a flrong foil, 

 not eafy to be wrought, may be rendertd perfeclly light 

 and loofe ; but by mixing it with earth of a nature contrary 

 to tV.at which it is intended to correft, and in a proportiou 

 fitted to the nature of the foil on which it is to be laid, it 

 will prove a good manure for alniolf any fort of land. 



And Mortim.er has even affeited that it v.ill alter and ' 

 change the very nature of the foil, and turn it into a rich 

 black mould. As it abounds with vegetable matter derived 

 from ilie tree to which it belonatd, and is flrongly impreg- 

 nated with animal materials by the length of time which it 

 has remained in the tan vats, in contact with the flcins and 

 hides of animals, it muff necL-ffarily prove beneficial as a ma- 

 nure where judicioufly applied. 



When laid on grafs-land it has been recommended to be 

 fpvead out over it foon after Michaelmas, that the winter 

 rains may wafli it into the ground to the roots of the graifes, 

 as when laid ci; in the fpring, it is apt to burn the grafs, and, 

 iniUadof improvii'git,todo cop.iiderable iniv.ryforthat feafon. 

 But when employed on arable land it fliould be applied and 

 fpi cad before the lall ploughing, in order that it may be turned 

 down lightly into the foil fo ns the fibres of tiiecorn mayeafily 

 reach it in the fpring ; when it lies too near the furface, it 

 has however been fuppoled to forward the growth of the 

 crop at too<arly a period, and to be nearly confumed in the 

 fpring, when the nouriflimentis chiefly wanted for its fuppoit. 



Ill his work on gardening and agriculture, Mr. Bradley 

 favs, he advifed a gentleman to whom a coiifiderable quantity 

 of bark was left, upon the expiration of the Icafe of a tan 

 yard, to lay fome of it upon a piece of flubborn four land ; 

 w'hich he did with fuch fuccefs, that his produdt was admired 

 by all the gardeners and farmers in the neighbourhood. 

 For fuch foils, he thinks it fhould he mixed with a fandy 

 mould or earth ; and that one third of bark to two thirds of 

 fuch mateiials will be a fufficient proportion for clays in gene- 

 ral, laying on about one hundred and fifty cart loads upon the 

 acre. 



Worlidge remarks, that the barks or rinds of other trees, 

 though not of fo high a value as that of the oak, which is 

 the fort principally ufcd by tanners, muft of neceflity enrich 

 either corn or pafture grounds, if broken into fmall pieces, 

 and laid upon them. 



It has been found from experience, that by mixing cauflic 

 lime witii tanners bark, in the proportion of about two parts 

 of the latter to one of the former, the converfion of the 

 bark into vegetable mould may be greatlypromoted, and that 

 the compofition when employed as a top dreffing for either 

 turnips or grafs proves an excellent manure, promoting the 

 growth of the crops in a rapid manner. 



Bark, in Gardening, comprehends the exterior parts or 

 coverings of trees, plants, and vegetables, and alfo fuch 

 fubllances in their dead flate after being feparated from 

 them, and employed for diflVrent purpofes. 



The bark of trees, &c. is in itfelf of a hard porous tex- 

 ture, and adheres loofely to the liber, or inner bark. It is 

 flated by Dr. Darwin, in his Philofophy of Gardening and j 

 Agriculture, that the barks of the trunks of trees are fimi- I 

 lar to thofe of their roots, and may be efleemed a part of 

 them, as tiiey confifl of an intertexture of the veffels which 

 defc^nd from the plume of each individual bud to the radi- 

 cle of it, and conllitute its caudex. The bark of the root 



