y - 



being remarkable for their adhesiveness, especially when mixed with other materials. Being- deprived of the 

 essential oil, these resins do not produce the same stimulating effeets as other preparations, and may be 

 considered as possessing astringency without pungency. 



Colophony is of considerable use iu the arts. It enters into the composition of several varnishes, and is 

 sometimes substituted for sandarach. Musicians rub the bows and strings of violins with it, in order to take 

 ott the more greasy particles, as well as to counteract humidity 



fi» 



TAR. 



(Pix Uqidda Tinea.) : 



nir\a, utTo-a, uypcc, Kc^vc? of the Greeks. 



Pia; liquif/a, of the Romans, and of most modern Pkarmacopceice. 

 Goudron, of the French. 



This well known substance/ obtained from the roots and other parts of old Pines by a sort of dMHatw 

 per descensum, differs from the native resinous juice in having acquired a disagreeable empyreumatic quality 

 fi*om the action of the fire, and in containing the saline and mucilaginous parts of the tree mixed with the 

 extractive and the oily. The Scotch Pine is the species from which most of the Tar used in this country is 

 procured, and perhaps yields it equally good with its congeners. It is curious to remark how little the 

 process employed in many countries differs from that which was followed by the ancient Macedonians, and 

 ^which is circumstantially described by Theophrastus, in the third chapter of his ninth book, where he tells 

 us that the billets were placed erect beside one another, and that they were afterwards covered with turf to 

 prevent the flame from bursting forth, in which case the tar was lost. The stacks were sometimes, he says, 

 one hundred and eighty cubits in circumference, and sixty, or even one hundred, in height." These huge 

 heaps of wood being set on fire, the tar was made to flow from them in channels cut for that purpose. As 

 all the trees of this genus yield the same substance when treated in a similar way, it is probable that the 

 ancients did not confine themselves to one species for obtaining it, any more than the moderns, and that some 

 variety was occasioned in the product according to the different management of the fire, and in the cooling. 

 Hence arises the confusion, and the difference of opinion among commentators respecting the terms Cedria, 

 Cedrceleon, Piss(cleon, &c. which, after the most industrious collation of passages from Theophrastus, Dios- 

 corides, Galen, and Pliny, it is scarcely possible at this day to refer to the precise substances which they 

 were intended to designate. But, we shall now proceed to point out the mode of procuring tar which 

 Duhamcr states to have been practised in the Valais, and which seems to be the best that has been 

 adopted.*" 



■ It is usual to cut down the Pines intended to be burnt for the extraction of Tar, in the course of the 

 summer. The operators, knowing the quantity that will be wanted, regulate the extent of the hewing and 

 tearing up of the trees so as that the materials may be neither too green nor too dry at the time of preparing 

 their ovens, for, to make good tar, they should not be more than half dry. As all parts of tlie Pine (the 

 trunk, branches, and even the bark) yield this substance, the branches are cut of a length proportiouate to 

 the size of the oven, and the thicker parts chopped into little billets similar to what arc used in faggots. 

 The ovens are shaped like an eg^ placed on its smaller end, and are composed of earth and stone, the floor 

 being formed of one or more pieces of freestone, which are very nicely joined and hollowed like the inside 

 of an egg-shell. On one side there is a hole about an inch and a half in diameter, and six inclies in depth; 

 to the external orifice of this, and five or six inches higher than the bottom of the oven, a gun barrel of a 

 large caliber is affixed, and there is a large iron grate placed at the bottom of the oven. The dimensions of 

 the oven vary according to the quantity of wood intended to be burnt, the largest being about ten feet high, 



" As a summary definition of Tar, the words of Piiny perhaps cannot be improved. " Ph nihil aliud est, (says he), ^iiam combusta: resino} 

 Jlu.Tus." (See Lib. 23. cap, 1.) . 



° '* H o-uvStinf xuxXwv r ej'ifojixovia; xxt oicHov Tr-KX^uv, tif v^of Si tgnJcouTa;, ttXiov n ■rcivrtxovTu, n ixxrov ixi^ipiirifUii." (LoC. SUpra citat.) 



_ ^ ^ 



" Trait6 des Arbrh, Tom. 2. p. l60. . ■ 



'' The reader may be gratified in consulting the work of John Conrad Axtius, (entitled, " Tractatus de Arborihus Coniferis et pice conftcienda." 

 lona. 1679. 12") which contains much curious matter on this subject, as well as on the products of Pines in general. 



20 



