220 



PRUNING AND THINNING. 



PT. IV. 



although to make up the diameter of a tree from the 

 rings on one side of its centre the width of these rings 

 must be reckoned double, to ascertain the age of the 

 tree the number of the rings on one side of its centre 

 must be reckoned single. The width of a half dia- 

 meter must be doubled to make a whole diameter ; 

 but when you count the years of a tree you must not 

 double them to get at its age. ' There's ne'er a villain 

 in all Denmark but he's an arrant rogue.' These 

 three truisms seem equally profound and equally pal- 

 pable. Yet I think that Adanson may have made the 

 slip, and, with the tree standing, may have failed to 

 perceive that the number of rings on the half diameter 

 is the same as on the whole diameter ; and that, 

 having doubled their width in completing the space or 

 diameter, he has also doubled their number in reckon- 

 ing the tiine or the age of the tree. If so, the number 

 of years he has given must be halved^ and 2,575 years 

 would be the age of the tree ; a pretty good age too, 

 since it Avould nearly take us back to the time of 

 Eomulus ! Even for this age, however, the growth 

 must have been slow ; little more than the fifteenth 

 part of an inch for the width of each annual ring. If 

 the annual ring were one-eighth of an inch in width, 

 the tree would attain the size of thirty feet in diameter 

 in 1,440 years ; if the ring were one-fourth of an inch 

 in width, in 720 years.'" 



* The simplest view of tlie case is this : — The baobab is thirtj 

 feet in diameter — 360 inches. If the width of the annual ring 



