636 THE POPULAR SCIENCE MONTHLY. 



till it has been improved by cultivation. An article of cork, a bottle- 

 cork, for example, is therefore doubly an industrial product: first, as a 

 substance, the qualities of which have been brought out by perfected 

 processes of cultivation and harvesting ; and, secondly, as an article 

 that has been manufactured, either by the hand of man or by a machine. 

 It will hence be profitable to study the processes of cultivating and 

 gathering the cork, and the various industrial applications to which 

 the substance lends itself subjects concerning which no well-composed 

 account has yet been given. 



The bark of the cork-oak is composed of two distinct concentric 

 layers : an inner sheet, which is the active part of the bark, and corre- 

 sponds with the liber of other trees ; and a thicker, outer zone, com- 

 posed of light, compressible, spongy substance, only slightly permeable 

 to liquids, and constituting the cork proper. Wherever upon the body 

 of the tree the inner sheet, or "mother " bark, is destroyed, no further 

 formation of bark or wood takes place ; and even a narrow decortica- 

 tion clear around the tree would cause it most certainly to perish. 

 The other coat, or cork, is inert, and does not contribute to the active 

 functions of vegetation ; and this explains how it is possible to strip 

 the cork-oak of its corky envelope without endangering the existence 

 of the tree. The inner bark, moreover, if left untouched, will form 

 yearly new layers of cork which may ultimately, when they have be- 

 come thick enough, be removed in their turn, and furnish the cork of 

 commerce, also called female cork. 



According to the most excellent account of the process, given by 

 M. Matthieu, in his " Flore forestiere," the clemasclage, or removal of 

 the cork, is done in July or August, when the condition of the sap- 

 movement permits an easy separation from the "mother." The work 

 must be suspended when the winds of the sirocco are blowing, for 

 they would destroy the vitality of the inner bark by drying it up im- 

 mediately ; and about two per cent of the trees are likely to be lost, if 

 the operations are crudely performed, by exposure to the glare of the 

 sun. The renewed young bark, if it is permitted to form itself in 

 contact with the air, is also exposed to the attacks of insects and liable 

 to become cracked. To obviate these disadvantages, M. Capgrand 

 Mothes, a French sylviculturist, has devised a method of clothing the 

 stripped oak-trees, by replacing and leaving upon them for a while the 

 cork -bark which has been taken from them. Having been removed 

 in the shape of two half-cylinders, it is easily tied back upon the trunk 

 with wires, while the joinings are covered with strips of paper. The 

 dress is taken off at the end of three months, when the cork which has 

 been utilized to compose it will be found to have become better sea- 

 soned than it would have done by the usual method of stacking it. 

 The new bark, under this protection, will have formed only a thin, 

 superficial crust, and that free from cracks and the marks of insect- 

 stings. This process, which furthermore protects the trees against hot 



