THE TECHNOLOGIST, 



NOTES ON THE ECONOMIC APPLICATION OF BARKS. 



BY JOHN R. JACKSON. 



Tanning Barks. 



The tanning of the hides of animals is an art of very great antiquity. 

 Pliny speaks of leather as the invention of Tychius of Bceotia ; one of 

 the oldest substances in use for the purpose of tanning, is undoubtedly 

 oak-bark, and for a considerable time it was considered the only article 

 suited for such purposes. Although tanning can be traced back to so 

 remote an age, the ancient tanners seem to have known little or nothing 

 of the chemical action of the properties of the bark upon the hide ; 

 but, of late, keeping pace with the advancement of all other branches 

 of knowledge, changes have taken place in this work ; new barks and 

 other substances which have been found to contain the required prin- 

 ciple have been tried, and consequently we have many other materials 

 in the market, and new ones being frequently added. The demand for 

 oak-bark became so great that in the year 1765 the Society of Arts were 

 led to offer a prize for a substitute for use in tanning, and the applica- 

 tion of oak-sawdust, which, however, had been previously used suc- 

 cessfully in Germany, was the result ; other substances followed, such 

 as oak-leaves, &c, yet the bark of the oak maintained and still holds 

 ita superiority over them all, and is always used for the best kinds of 

 leather. The present consumption of oak-bark for tanning purposes is 

 enormous ; besides the home supplies, which amount to between 

 200,000 and 300,000 tons yearly, we annually import about 4,000 tons 

 from the Continent. Some interesting information on Tanning Sub- 

 stances will be found at p. 289, vol. 1, Technologist. 



Quercus saler, L. — The cork-tree, a native of the South of Europe 

 vol. in. z z 



