THE ACACIA. 



231 



liarity to the fact, that its principal roots extend 

 themselves close to the surface of the ground, 

 where the soil is always richest. Hence the 

 growth is at first very rapid ; but when the roots 

 cease to extend, all the surface-soil which they 

 traverse being exhausted, the growth of the tree 

 is retarded. But though it alters little in size 

 after it has reached its fiftieth or sixtieth year, it 

 is long-lived. The first tree that was introduced 

 into Europe by Monsieur Robin and planted in 

 the Jardin des Plantes at Paris, in 1635, is still 

 in existence, and is now seventy-five feet high. 

 About the year 1815 it shewed symptoms of de- 

 cay, but the branches being lopped, the trunk has 

 shot out with redoubled vigour. This is, in all 

 probability, the oldest American tree in the east- 

 ern hemishere. 



The wood of the Acacia is supposed to unite 

 the qualities of strength and durability to a degree 

 unknown in any other kind of timber ; in con- 

 sequence of which it has, for many years, been 

 employed throughout America and Europe in the 

 construction of the wooden pins, called trenails 

 {tree-nails), which are used to fasten the planks to 

 the ribs or timbers of ships. The history of the 

 first application of the Acacia to this purpose, is 

 given at length in Dr. Hunter's edition of Eve- 

 lyn's Sylva, and is well worthy of repetition. It 

 is contained in a letter, dated July 25, 1782, from 

 Joseph Harrison, Esq., of Bawtry, to Dr. Hunter. 



The first experiment that I know of, respecting 

 the application of the timber of the Locust-tree 

 to any purpose in ship-building was in Virginia, 

 where I resided sometime about the year 1733 : 

 and there, happening to be acquainted with an 



