COMPARATIVE VALUE. 



277 



let us consider what merit this tree may possess from au 

 economic point of view, and what its natural and proper uses 

 really are. 



Comparative experiments,^ made a few years ago by an 

 employd of the French Government in the dockyard at 

 Toulon, on the wood of the ailanthus, show the following 

 results. The ailanthus timber was from trees from twenty- 

 five to thirty years old, and presumably was in a similar con- 

 dition of dryness ^ as the other woods tested in connection 

 with it. 



These experiments show that the wood of French-grown 

 ailanthus is in weight between European oak and European 

 elm, and that it is actually considerably stronger and more 

 flexible than either. I have had the specific gravity of three 

 specimens of the wood of the ailanthus, grown in New Eng- 

 land, determined, because the weight of any wood will indi- 

 cate more readily than any other possible test its value for 

 purposes of construction or fuel, as, in general terms, the 

 heavier a wood is, the harder and stronger it is, and the 

 greater the amount of heat-giving qualities which it possesses. 



These determinations give the following result : — 



Specific gravity of ailanthus-v?ood from a young tree grown 

 in Portsmouth, R.I. 



Specific gravity of ailan thus-wood from trunk of a tree twenty- 

 seven years old, grown in Brookline, Mass. 



Specific gravity of ailanthus-wood from main branch of the 

 Brookline tree 



.607 



.593 



Average 



.042 

 .014 



1 See Comptes rendus de I'Academie des Sciences, Paris, vol. Ixi. p. 344. 



2 Undoubtedly these determinations were made on wood simply air-tlried 

 and in a proper state for use. This supposition accounts for the discrepancy 

 between the weight of the wood of the French and New-England ailanthus. 



