ON THE TRADE IN COUK BARK. 43 



cessary to destroy it. The inventor of this admirable adjunct to health 

 and comfort has, therefore, turned to valuable and profitable account 

 that which was heretofore a nuisance in the cork factory. These minute 

 bits of cork are placed between two layers of oiled linen, or caoutchouc 

 cloth, thus preserving the sleeper entirely from all hazard of damp, the 

 nature of cork being to resist it. On sea-board, besides excluding all 

 the " disagreeables" that generally haunt a vessel during a long voyage, 

 it serves as a life-buoy in case of shipwreck — either to the individual or 

 to the boat ; its value, therefore, to the emigrant is incalculable. 



Cork should be chosen in fine layers or boards, not broken nor knotty, 

 smooth when cut, and of moderate thickness. 



The cork-oak is abundant in Portugal, Spain, especially Catalonia 

 and Valencia, Italy, the South of France, and parts of Northern Africa. 

 In France it is found in great abundance in Languedoc, Provence, the 

 environs of Bordeaux, and the department of Var. 



M. Casimir De Candolle has recently published a dissertation upon 

 the manner in which cork is formed in the cork-tree. 



The bark of all trees consists of a parenchymatous or soft cellular 

 tissue, and of a harder ligneous tubular tissue. In most cases the latter 

 is most abundant ; in the cork the former constitutes the mass of the 

 bark, and hence its elasticity and the facility with which it is cut in all 

 directions. When, however, it is first generated, the bark of the cork- 

 tree is far less elastic than it becomes subsequently, which is owing to 

 its consisting, in the first instance, of a large proportion of woody 

 matter. When the latter is once formed, which takes place in the first 

 year of its growth, it never increases, however long the bark may remain 

 in a living state ; but the parenchymatous substance will go on growing 

 as long as the bark is alive, a provision of nature connected with the 

 annual increase in diameter of wood, and the necessity of the bark 

 giving way to the pressure from within. 



If the growth of the parenchyma is prolonged and rapid, a corky 

 substance is the necessary consequence, as in certain kinds of elms, the 

 common oak itself, and many other trees ; but it does not occur in any 

 European tree in such excess as in the cork. As soon as the bark dies, 

 it of course ceases to grow, and then, not distending as it is pressed upon 

 from within, it falls off in flakes which correspond to the layers that are 

 formed annually. 



The careful removal of this outer or dead bark from the cork-tree 

 does not in any way injure it ; on the contrary, it is stated that the tree 

 grows more vigorously and lives longer in consequence of being thus 

 stripped. After a tree has attained to the age of 26 to 30 years, it may 

 be barked, and the operation can be subsequently repeated every eight 

 or ten years, the quality of the cork improving with the increasing age 

 of the tree. The bark is taken off in .1 uly and August, and trees that 

 are regularly stripped are said to live for 150 years or more. The bark 



