MARKS AND SUBSTANCES POUND IN TREES. 313 



sufficient to obviate the brittleness of the wax in its pure state, 

 without giving it any unpleasant smell, or materially impairing the 

 ^brilliancy of its flame. A mixture of three parts of the vegetable 

 wax, with one part of the bees-wax, also makes very excellent 

 candles. 



[Humboldt and Bonpland. Pantolog % Phil. Trans, Barton. 



CHAPTER VII. 



EXTRANEOUS MARKS AND SUBSTANCES FOUND IN THE 

 TRUNKS OF TREES. 



In a preceding section, on the physiology of plants, it has been 

 observed, that the trunk consists of hard wood, constituting its heart; 

 soft wood or alburnum ; inner bark or liber!; and outer bark or cor- 

 tex : and that the hard wood is produced and increased by an an- 

 nual formation of new alburnum or liber. Wildenow supposes the 

 latter j aud that the liber of the one year is in the next converted 

 into alburnum, and the alburnum of the same year into hard 

 wood. Mr. Knight conceives the liber is not concerned in this 

 conversion, and that the alburnum alone is converted into hard 

 wood. In either case, it is easy to foresee that any durable marks 

 or foreign substances introduced through the bark of the tree down 

 into the soft wood, must necessarily, as this wood becomes con- 

 verted into hard wood, and covered witli new annual layers of soft 

 wood, be transferred by degrees towards the interior of the trunk, 

 and be found in the hard wood, or heart of the tree, instead of in the 

 alburnum or external part. 



We hear curious accounts of letters, rude cuts or engravings, and 

 foreign bodies, being found in the middle, or near the middle, of the 

 trunks of many trees ; to the great astonishment of those who have 

 made the discovery, and have not been aware of the true nature of 

 the growth of the trunk, which we have thus endeavoured to point 



