48-4 BARK. 



birch. Even chestnut-wood* is now used in Savoy for the pro- 

 duction of tannic acid. The oak heads the list both for ricliness 

 in tannic acid and quantity of production, and oak-bark is 

 at present reputed as the best tannin<^ material in (Germany, 

 Belgium, and England. 



The tanner considers only young oak-bark suitable for render- 

 ing leather water-tight, a faculty more or less wanting in other 

 tanning materials, and which, according to chemists, is owing to 

 the starch in the young bark. 



As regards tanning materials from foreign countries, the 

 following list is given : — Catechu, an extract rich in tannic acid, 

 from the wood of an Indian tree. Acacia Catechu, Willd., and the 

 leaves of a Malayan shrub, Uncaria Gambia, lloxb. ; also in 

 small quantities from the nuts of the Indian palm (Areca 

 Catechu, L.) ; Dividivi, the dried husks t of the pods of a 

 small tree, Caesalpinia Coriaria, Willd., which grows in Brazil 

 and the West Indies [and has been introduced into the East 

 Indies. — Tr.] ; Sahla consists of the pods of a Mimosa ; 

 Valonea, of the cups of acorns of Quo'cus A'lgilops, which grows 

 chiefly in the Levant and Greek islands, &c., it is a very 

 powerful tanning agent, chiefly used in the tanneries of Southern 

 Europe, and is now being increasingly used in Germany to 

 strengthen weaker tanning substances. A very powerful tanning 

 material is Quebracho wood {Aspidosju'rma Quebracho), from 

 the river Plate ; it is cut into shreds, and used with tanning 

 bark ; Myrobalans, the fruits of Terminalia Chebula, T. IxUerica, 

 and 7'. citriii'i, are largely imported into Europe from India. 



[Besides the above substances mcntioiKHl by Gayer, Mimosa bark 

 from various Australian acacias — chiefly (A. harpo2>hi/Ha) from 

 Queensland, tlie black wattle {A. mol/isdma), tlie gold wattle 

 {A. I'l/cnantha), the Tasmanian silver wattle (A. leucophi/lla) and 

 {A. cyi()iojilti/lla) — is largely imported into the United Kingdom ; and 

 Hemlock bark, the bark of Abies canadensis, is the most important 

 tanning material in the United States, its extract being imported 

 into Europe. At Cape Town, the l)ark of Acacia srth'rpia, a naturalised 

 W. Australian species, is the mainstay t)f the tainiL'rics.--Tn.] 



* [There is a factory near Stuttgart in Wiirtteniburg, wliere eliestnnt-wood is 

 cut into shreds and Ijuiled-down for the ])iirj)ose. A smnlar factory at Nancy, in 

 France, uses 2,600 loads of oak-womi aiimuilly, the wood being taken from tin- 

 refuse of fellings in oak-forests, broken luanclies, stumps, roots, kc. (l3oj)iie, 

 o]>. cit. p. 108.)— Ti:.] 



t [The seeds contain an oil injurious to leather and must be removed. — Ti;.] 



