WEIGHT RELATIONS. 



15 



Siiice, iu the determination of the specific gravity above given, wood of the same per cent of 

 moisture (as is the case in the values of strength) was not always involved, and also since the test 

 pieces, owing to size and shape, can not perfectly represent the wood of the entire stem, the 

 following results of a special inquiry into the weight of the wood represents probably more 

 accurately the weight and with it the strength relations of the four species. 



WEIGHT RELATIONS. 



[These data refer to the average specific, weight for all the wood of each tree, only trees of approximately the same age being involved.] 



0.53 



Shortleof. 



131 



10 

 0.51 



32 



81 

 (77) 



* The values of strength refer to all tests, and therefore involve trees of wide range of age and consequently of quality, especially those 

 of Longleaf ; involve much wood of old trees, hence the relation of weight and strength appears less distinct. 



From these results, although slightly at variance, we are justified in concluding that Cuban 

 and Longleaf Pine are nearly alike in strength and weight and excel Loblolly and Shortleaf by 

 about 20 per cent. Of these latter, contrary to common belief, the Loblolly is the heavier and 

 stronger. 



The weakest material would differ from the average material in transverse strength by about 

 20 per cent, and in compression strength by about 30 to 35 per cent, except Cuban Pine, for which 

 the difference appears greater in transverse and smaller in compression strength. It must, of 

 course, not be overlooked that these figures are obtained from full-grown trees of the virgin forest, 

 that strength varies with physical conditions of the material, and that therefore an intelligent 

 inspection of the stick is always necessary before applying the values iu practice. They can only 

 represent the average conditions for a large amount of material. 



DISTRIHTTION OF WEIGHT AND STRENGTH THROUGHOUT THE TREE. 



IFeight and strength of wood at different heights in the tree. 



NOTB. Relative values are indicated by italic figures. 



