Bark and Bark-stripping. 



By ALFRED J. BURROWS, Pluckley, Kext. 



The operation of stripping and properly harvesting bark in a cold 

 wet season is one calculated to tax to the uttermost the patience, skill, 

 and energy of the forester. During the ascent of the sap there is a 

 period at which, if an oak be felled, easy and expeditious stripping is 

 the result ; while, if it be delayed beyond that time, the work becomes 

 more difficult, and the quality of the bark also deteriorates. 



The bark of exogens consists generally of three parts, — the outer 

 skin, o\: cuticle ; the solid part, called also the cortical integument; 

 and the inner bark, or lihcr. In most trees the outer skin is so 

 unyielding that it cracks and sometimes peels ofiF. The liber is 

 generally very thin; and every year a concentric zone of it is formed 

 inside that of the preceding year. Though the bulk of it appears to 

 be a mass of spongy fibrous matter, the inner layer is easily separated 

 from the others. At an early period in history the liber was stripped 

 off in layers, and formed into leaves for writing upon : hence its name. 



Besides acting as a protection to the delicate structure of the young 

 plant, the bark serves to convey the descending fluid or elaborated sap 

 back to the roots, after a portion of it has passed inwards through the 

 medullary processes. 



In the present paper we purpose to confine our attention to the use 

 of bark in tanning leather, and to give a brief account of the method 

 adopted in stripping and harvesting. 



The art of preparing leather by using substances possessing 

 astringent properties is said by Pliny to have been practised by 

 Tychius of Boeotia. But though the practice continued, but little 

 inquiry was made into its principles till about the middle of the last 

 century, when a temporary scarcity of bark for tanning purposes 

 directed attention to the subject. This resulted in the discovery that 

 many other vegetable substances contained tannin. The Germans 

 were using bird) bark, gall-nuts, and pulverized heath ; the Russians, 

 willow bark ; the West Indians, the bark of tlie red mangrove tree ; 

 the Italians, leaves of the myrtle ; and the Corsicans, laurel leaves. 



In France, M. Seguin made many important discoveries in relation 

 to the process of tanning, which were published in J75G. Sir 

 Humphrey Davy ascertained that all substances possessed of an 

 astringent taste contained tannin. He found it abundant in the juices 



