forefts, confirming intirely of birch. The foil 

 in fome parts of thefe wafles being very {hal- 

 low, or very loofe, the trees had not a fuf- 

 ficient footing for their roots, and became an 

 eafy prey to winds. In thefe places Maupertuis 

 found as many trees blown down, as {landing, 

 He examined feveral of them, and was fur- 

 prized to fee that in fuch as had lain long, the 

 fubftance of the wood was entirely gone; 

 but the bark remained a hollow trunk without 

 any figns of decay. I have heard, that the 

 bark of the black cherry-tree in North America, 

 which grows there to a great fize, has the fame 

 property. 



Among elegant, pendent trees, the acacia 

 fhould not be forgotten; though the acacia, 

 which we have in England, (called by the bo- 

 tanift, the roblnia] is perhaps only a poor fub- 

 ftitute of this plant in it's greateft perfection. 

 And yet even ours, when we have it full grown, 

 is often a very beautiful tree, whether it feathers 

 to the ground, as it fometimes does ; or 

 whether it is adorned with a light foliage 

 hanging from the ftem. But it's beauty is 

 veiy frail. It is of all trees the leaft able to 

 endure the blaft. In fome flickered fpot, it 



F 4 may 



