of Waiile Bark, dv. 221 



should suffer by what may be called a mere fancy of the 

 trade. 



There is inducement to redeem the character of the 

 extract in the estimation of our shippers and manufacturers, 

 as it is likely to be much more extensively used than here- 

 tofore. The article on tanning in the Penny Cyclopoedia 

 contains a notice of at least one successful attempt to 

 shorten the process by the use of extract ; and it cannot be 

 believed that this time-saving age will long submit to the 

 tedious method hitherto followed, when it is known that 

 hides have been tanned in a few hours ; while from six months 

 to two years is taken in the usual way. 



The principle is now well understood by the intelligent 

 tanner ; yet, though every one knows that bark is used in 

 tanning, few ordinary persons are so fully aware of the 

 manner in which the transmutation takes place in the hide 

 but that a brief explanation may render the subject more 

 clear to them. 



There is a chemical affinity, or attraction of combination, 

 between tannin or the astringent principle of bark and all 

 kinds of gelatin. This may be shown by pouring a small 

 quantity of the extract into a solution of glue or other 

 gelatinous substance; the two (the tannin and glue) combine 

 and form a compound, leaving the water which held them in 

 solution free. 



The skins of animals being composed of gelatin attract 

 the tannin from the bark, or rather its infusion, when they 

 are placed together in the pits ; but as the structure of the 

 skins is extremely complicated and minutely cellular, the 

 tannin is required to penetrate each cell, and combine with 

 its sides, or fill it, before the skins are completely tanned. A 

 single infusion will not carry a sufficiency of the tanning 

 principle to effect this, and hence arises the tediousness of 

 the process ; for the water of the first infusion, after pene- 



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