164 TOBACCO. 



By moans of the handle of the axe, which is shaped like a wedje 

 forced into the vertical cut, the cork is then loosened and stripped 

 from the livinfrhark beneath it, the whole covering of the tree beinc 

 often taken away in a single piece, although it is more commonly re- 

 moved in two pieces. The process of barking is very easy when 

 the sap is abundant. 



The cork-tree must be about forty years of age before its bark has 

 any commercial value ; that of a tree of twenty years is always 

 treated as rubbish. An oak a century old may furnish 200 lbs. of 

 marketable cork ; as many as 480 lbs. however have been taken 

 from a single tree ; the mean produce may be reckoned at about 106 

 lbs. per tree ; to fit it for the market, cork undergoes a variety of 

 preparations which need not detain us here. 



LEAVES. 



The herbaceous parts of vegetables have all a very similar com- 

 position, if they be regarded in the most general point of view. The 

 leaves and green stems, along with the woody fibre which forms in 

 some sort their skeleton, always contain albumen or an analogous 

 azotized principle, saccharine and gummy substances, chlorophylle, 

 wax, fatty and resinous substances, free or combined acids, and fre- 

 quently also essential oils. Such is the general constitution which 

 chemists agree in assigning to clover, hay, leaves, in a word to green 

 forage of all kinds ; nevertheless, to this constitution, which may be 

 regarded as standard, we have frequently other particular matters 

 added, some of which we have already studied, and which by their 

 medicinal properties, or the economic uses they possess, render the 

 plants that contain them of high importance in an agricultural point 

 of view. I shall here only speak of two of these plants, tobacco 

 and tea, the leaves of which, almost in universal use, are a source 

 of great commercial prosperity to the people who cultivate them. 



Tobacco, {Nicotiana iabacum,) a native of America, appears to 

 have been introduced into Spain and Portugal about the middle of 

 the sixteenth century by Fernandez de Toledo. Its name is gen- 

 erally believed to be derived from that of the Island of Tobago, one 

 of the West India islands, at no very great distance from the coast 

 of Venezuela, whence the first importations were made. Nicot, the 

 French ambassador to Portugal, first made its use known in France, 

 whence the name nicotiana. At the present time, the cultivation of 

 tobacco appears to have spread almost over the whole surface of the 

 globe. 



Tobacco requires a somewhat friable soil, rich in humus ; it con- 

 sequently succeeds in lands just broken in. In America the mode 

 of cultivation and of preparation are almost everywhere the same. 



In Venezuela the seed is sown in a very ricli loam, and after from 

 forty to fifty days, the young plants are transplanted in rows, distant 

 a little more than three feet from one another, the plants being about 

 two feet apart ; the transplanted plant is generally covered with a 

 banana leaf <br a few days to preserve it from the burninjj rays of 



