EXOGENS. 



157 



The produce of the latter plant employs the labor of a 

 million and a half of people in England alone, and fur- 

 nishes clothing to hun- 

 dreds of millions. 



The Tea family (TERN- 

 STR^MIACE^E) has in it 

 the beautiful Camellias 

 of Japan, and the plants 

 which furnish tea, (Thea- 

 viridis and Bohca^ The 

 use of the leaves of these 

 plants is immense, no 

 less than fifty-six mill- 

 ions of pounds being im- 

 ported into Great Britain 



in a single year, (1846.) FlG - 66 - The Cotton-piant, 

 The bitter principle in tea, called theine, may be pro- 

 cured by adding a slight excess of acetate of lead 

 to a decoction of tea, filtering hot, evaporating, and 

 subliming. 



The Orange family (AURANTlACEyE) contains about a 

 hundred species. The plants contain receptacles of vola- 

 tile oil. The fruit has an acid or subacid pulp, and the 

 wood is compact. The Orange, Lemon, Lime, Citron, 

 and Shaddock belong here. 



AcERACEvE, the Maple family, contains the Maple and 

 Sycamore, (Acer pseudo-platanus^} The Sugar Maple 

 (A. saccharinum) yields a sap from which sugar is manu- 

 factured. 



The Mahogany family (CEDREIACE^E) contains plants 



with an aromatic fragrance. Swietenia Mahogoni sup- 

 14 



