217 



inadeuse of, must be through the bark, 

 where it has been clear of branches ; no 

 matter though it may curve considerably. 

 There should be at least as many inci- 

 sions, as the tree is half yards round. 



This operation can only be performed 

 upon old, thick-barked trees, when the 

 sap is stirring. Its effect is, the loosen- 

 ing of such bark ; and thereby not only 

 assisting the circulation of the sap, gene- 

 rally ; but likewise opening it a free pas« 

 sage along the incision; as such would 

 soon be filled with new free grown bark ; 

 underneath which, that fluid would pass 

 readily to the head. 



PL VII. is an oak board, cut from a 

 tree, infested with unnatural branches. 

 The dark marks are their roots in the 

 wood. The grain, or sap vessels appear 

 curving in every direction ; in many 

 places, more particularly near the bot- 

 tom, they lie nearly across. On breaking 

 p 



