BAR 



exotics tliat require the aid of an nnirorm dc»rce of arti- 

 ficial heat in this dimate. See Bark-Bed, and Bark- 



P.T. 



B.4,RKS of Trees, {Chemieal Analyjts of). Since the time 

 that chemifts have intrudnccd a coiifideiable degree of 

 miniitenefs and comparative accuracy in the analylis of vege- 

 table matter, many of the pencnil claffiiications of medical 

 chcmillry have been found inconvenient and liable to error. 

 This is particularly the cafe when vegetable fubllances de- 

 figned for chen:ical examination, are claded anatomicuUy, or 

 according to the ufes which they fulfil in the economy of 

 the plant, rather than the properties which liiey exhibit 

 under the hands of the chemift. Thus, in the inftance of the 

 harlis of trees, fcacely any common chemieal charaftcr can 

 be affigned to them, as their compofition varies in almoft. 

 every order of plants, and as they partake largely of tlie 

 qualities of the common juice which circulates in the vege- 

 table. If there is any principle common to al! barks, it is 

 (befides water, an invariable ingredient in vegetable matter), 

 the ligneous fibre or infoluLle v.oody part, but even in this 

 refpeft fume very important differences occur in the leveral 

 fpecies which cannot be negk£tcd by the chenmt. 'J'he 

 fnbilances which render many barks peculiarly intcreiling 

 in the arts and in medicine are, Tannin, or the principle 

 which caufes feveral of them to be employed in the art of 

 tanning ; Extract, a fubilance varying conllderably in pro- 

 perties, and much ufed in medicine ; and the Gallic Acid, 

 the balls of many of the black dyes and pigments when in 

 conjunftion with iron. Thefe principles, however, are not 

 pecuhar to barks, but they are all foun I in other parts of 

 vegetables. We have an example of an excellent analyfis of 

 the bark of the Cinchona, by M. Fourcroy, to which arti- 

 cle we Ihall refer the reader who may wifli to have a good 

 fpecimen of the chemical analyfis of vegetables. 



Barks, general obfrvatloiu relating lo. From the experi- 

 ments of M. Buifon, it appears, that trees ilripped of their ^ 

 bark through the whole length of their ftems, die in about 

 three or four years. But it is remarkable, that trees dripped 

 in the time of the fap, and fuiTered to die, afford timber 

 heavier, more uniform.ly denfe, ftronger, and fitter for fer\ice, 

 than if the tree had been cut down in its heahliy ilnte. Some 

 thing of a like nature has been obferved by Vilruvius and 

 Evelyn. Mem. Acad. Scienc. 1738. 



As animals are furniflied with a panniculus adipofus, 

 ufually replete with fat, which invells and covers all the 

 flelhy parts, and fcreens them from external colds, plants 

 are enconipafFcd with a bark replete with fatty juices, by 

 means whereof the cold is kept out, and, in winter-time, 

 the fpiciilas of ice prevented from fixing and freezing the 

 juices in the velfels : whence it is, that forae fort of trees 

 remain ever green the year round ; becaufe their barks 

 contain more oil than can be fpent and exhaled by the fun, 

 &c. Ray's Wifd. of Go<l, &c. parti, p. 103. 



The bark has its peculiar difcaics, and is infefted with 

 infedls pecuhar to it. Wounds of the bark often prove mor- 

 tal. See Canker. 



There are a great many kinds of barks in ufe in the 

 feveral arts : fome in medicine, as the quinquina, or jefuit's 

 bark, macer, chacarilla, &c. others in dying, as the baik of 

 the alder, ; others in fpicei-y, as cinnamon, caffia lignea, 

 &c. the bark of oak in tanning ; others on other occafions, 

 as that of cork ; that of a kind of birch is ufed by the In- 

 dians for canoes capable of holding twenty-four perfons. 



Of the bark of willows and linden trees is ordinarily made 

 a kind of ropes. The Siamtle make their cordage of the 

 ba:k of the cocoa tree, wkich is alfo the cafe in moft 

 of the Afiatic and African nations. Iii ixalicy, fla.s and 



Vol. in. 



BAR 



Ivemp, with all their toughnefs, are only the fap-venTcls, or 

 hgiKous fibres of the bafk of thofe plants. 



The ancients wrote their books on barks, ffpecially thofe 

 of the afh, and tilia or lime-tree ; not on the exterior or 

 outer bark, but on the inner and finer, called philyia ; which 

 are of fodurable a texture, that there are manufcripts on it, 

 ftill extant, a thoufand years old. 



In the Eall Indies thty manufafture the harks of a cer- 

 tain tre& into a kind of fluff or cloth. It is fpun and droffcd 

 much after the manner of hemp. The long filaments fepa- 

 rated from it, upon beating and fteeping it in water, com- 

 pofe a thread, of a middle kind between filk aid common 

 thread : neither fo foft nor briglit as filk, nor fo hard or 

 flat as hemp. See Neuman's Works, p. 428. note. Some 

 ot t'.iefc fluffs are pure bark, and are calltd pinaffcs, biam- 

 bonnes, fee. In others tliey mix lilk with the bark, and 

 call them ginghams and nillas : the four.tahingees too arc 

 part filk, part bark, and are only diiliiiguifhed by being 

 ftnped. Tlie Japanefc make their paper of a fpeces of 

 mulberry tree. (See MoRus.) In the ifland of Otaheite, 

 the natives make their cloth, which i* of three different forts, 

 from three different kinds of bark ; that of the mulben y tree, 

 that of the bread-fruit tree, and that of the cocoa tree. That 

 made of the mulberry isthefinell and whiteii, and worn chiefly 

 by the principal people. It is manufactured in the follow- 

 ing manner. When the trees arc of a proper fize, they are 

 drawn up and tlripped of their bra.icb.es ; after which, the 

 roots and tops arc cut off; tiie bark of thefe rods being 

 then flit up longitudinally is eafily drawn off; and when a 

 proper quantity has been procured, it is dcpofitcd in fome 

 running water to foak, and kept dov/u by heavy ftonts ; 

 when it is fuppofed to be fufficiently foaked, the women 

 go down to the brook, and, ftripping themfelves, fit 

 down in the water to feparate tlie inner bark from the 

 green part on the out fide ; for this purpofe, they place 

 tiie under fide upon a flat fmootli board, and with a kind 

 of fhell fcrape it very carefully, dipping it continually in 

 the water, till nothing remains but the fine fibres of the 

 inner coat. Bting thus prepared in tlie afternoon, they are 

 fpread out upon ph.ntain leaves in the evening, and placed 

 in lengths of about eleven or twelve yards, one by tlic fide 

 of another, till they are about a foot abroad, and two or 

 three layers are alfo laid one upon the other ; care is taken 

 that the cloth fliall be in all parts of an equal thickncfs, fo 

 that if the bark happens to be thinner in a particular part 

 of one layer than the rell, a piece that is fomewhat thicker 

 is fclefted to be laid over in the next. In this ftate it re- 

 mains till the morning, when a great pait of the water 

 which it contained, when it was laid out, is either drained off 

 or evaporated, and the feveral fibres adhere togetlier, fo 

 that the whole may be railed from the ground in one piece. 

 It is then taken away and laid upon the Imooth fide of a long 

 piece of wood, prepared for the purpofe, and beaten by the 

 women. The inftrument ufed for this purpofe is a fqnare 

 wooden club, having each of its four fides or faces marked, 

 lengthw'iie, with fmall grooves or furrows of different degrees 

 of finenefs ; thofe on one fide being of a width and depth 

 fufSeicnl to receive a fmall packthread, and the others fiuei; 

 in a rcgiUar gradation, fo that the lail arc not more than 

 equal to fewing filk. They beat it firft with the coarfefl 

 fide of this mallet, keeping time like our fmilhs ; it fpreads 

 faft under the llrokcs, chiefly, however, in the breadth, and 

 the grooves in the mallet maik it with the appenaice of 

 threads ; it is fuccelfively beaten with the other fides, and 

 lall of all with the fincft, and it is then fit for ufe. Of this 

 cloth there are feveral forts, of different degrees of finenefs, 

 ill proportion as it is more or lei's beaten ; and the other cloth 

 4 M aiftf 



