530 ON THE ECONOMIC APPLICATION OF BARKS, 



and North of Africa. The inner hark is that used in the production of 

 leather, the corky portion heing devoid of tanning. The largest 

 amount of cork-hark and the "best quality is imported from Sardinia ; it 

 contains a large quantity of tannin, hut is seldom used alone, heing 

 usually mixed with valonea, &c. The greatest use to which the hark of 

 this tree is applied is for stoppers for bottles, and other similar applica- 

 tions which are so well known, and for which no substitute is equal. 

 The trees are usually allowed about sixteen years growth before the 

 bark is sufficiently thick for cutting. This is done by making longi- 

 tudinal and transverse incisions so as to allow the cork to be taken off 

 in flakes. These pieces are afterwards placed in water with heavy 

 weights upon them to flatten them, after which they are scorched or 

 blackened at a fire, chiefly for the purpose if giving a closer texture. 

 They are then packed in bales ready for the market. About 2,500 tons 

 of the bark are annually imported into tbis country. 



Abies canadensis, L. The Hemlock Spruce. — This is another well- 

 known material for tanning. The tree is a native of the colder parts of 

 North America, growing to a height of about eighty feet. The bark is 

 much used in the States, but an objection to its use in this country is on 

 accoimt of the red colour it imparts to leather. 



Alnus glutinosa, Willd. — A tree twenty or thirty feet high, native of 

 Europe and Western Asia. The bark has astringent properties, and is 

 used, as well as the leaves for tanning purposes. It is also employed 

 for dyeing black. The young shoots afford a dye of a cinnamon or 

 brownish yellow, while from the catkins a green colour is procured. 



Byrsonima spicata, Dec. — A small tree or shrub, native of St. Do- 

 mingo, Dominica, Brazil, &c, produces a bark which is used in those 

 countries for tanning. It is about a quarter of an inch thick, of a cin- 

 namon brown colour, covered with a whitish cuticle. 



Elazodendron croceum, Dec. — A tree about thirty or forty feet high, 

 native of the neighbourhood of the Cape of Good Hope. It produces 

 a thick fibrous bark of an earthy brown colour, and is much used in the 

 colony for tanning and dyeing, though it appears to contain very little 

 astringency. The tree is known as the saffron tree, probably from the 

 bark being covered with a resinous coating of a yellowish colour. 



Spondias lutea, L. — The Hog-plum of the "West Indies, where it is a 

 native, as well as of South America. It is a tree growing to a height of 

 about fifty feet, of very rapid growth, and is frequently planted for 

 hedges. The bark is about half an inch in thickness, of a very com- 

 pact, close texture, and a deep mahogany colour, the outer surface very 

 much cracked or furrowed. It is astringent, and has been successfully 

 used for tanning in British Guiana and the West Indian Islands. 



Mora excelsa, Bth. — A gigantic tree, growing to a height of from 

 120 to 150 feet, native of the forests of British Guiana. The bark is 

 considered a good tanning agent, for which purpose it is much employed. 

 It is about a quarter of an inch thick, very even and uniform through- 



