21 



The loug-leaf pine, then, is best distinguished by the following- fonr characteristics : 



(1) Width of the anuiial rings, having usually from 18 to 25 rings to the inch, as against 11 to 

 12 in the short-leaf and loblolly. Fewer rings to the inch would lend countenance to the suspicioji 

 that the material is not long-leaf. 



(2) Weight, whicli for partially seasoned wood averages about 48 pounds, being S to 12 pounds 

 heavier than short-leaf and loblolly. The lowest specific gravity found by Prof. .lolmson was O.CG 

 for tree 52, or 38 pounds. 



(3) Amount of resin, which produces, when the wood is cut across the grain with a sharp knife, 

 a polished and vitreous or horny appearance of the sunimerwood. This is, however, not a very 

 reliable sign, as other pines react in the same maTiner. Whether the pi-esence of large amounts of 

 resin account for the great weight and lor superior strength is still an open i|nestion. ' 



(4) Thickness of sap-wood, which, at least in the pines now cut for Innilier, is rarely over 2 or 

 3 inches wide, much less than the other pines with which it might be confounded. 



SPECIAL ADAPTATION!? OF LONGI.EAF YELLOW PINE. 



In regard to the use of this timber, Prof. Johnson makes the following statements regarding 

 the extensive tests here reported. 



The long-leaf pine timber is specially fitted to be used as beams, joists, posts, stringers in 

 wooden bridges, and as flooring when ([uarter-sawed. It is {n-obably the strongest timber in 

 large sizes to be had in the United States. In small selected specimens, other species, as oak and 

 hickory, may exceed it in strength and toughness. Oak timber, when used in large sizes, is apt to 

 be more or less cross-grained, knotty, and season-checked, so that large oak beams and posts will 

 average much lower in strength than the long-leaf pine, which is usually free from these defects. 

 The butt cuts are apt to be wind-shaken, however, which may weaken any large beams coming 

 from the lower i^art of the tree. In this case the beam would fail by sheai'ing or splitting along 

 this fiiult with a much smaller load than it would carry without such defect. These wind shakes are 

 readily seen by the inspector, and sticks containing them are easily excluded, if it is thought worth 

 while to do so. For highway and railway wooden bridges and trestles, for the entire floor system 

 of what is now termed "mill" or "slow-buriiing" c(uistruction, for masts of vessels, for orflinary 

 floors, joists, rafters, roof-trusses, mill-frames, derricks, and bearing jjiles; also for agricultural 

 machinery, wagons, carriages, and esiiecially for iiasseiiger and ti-eight cars, in all their parts 

 requiring strength and toughness, the long-leaf pine is pe(ailiarly fitted. Its strength, as compared 

 to that of short-leaf yellow piTie and white pine is probably very nearly in direct proportion to their 

 relative weight, so that pound for jiound all the pines are probably of about equal strength. The 

 long-leaf pine is, however, so much heavier than these other varieties that its strength for given 

 sizes is much greater. 



A great many tests have now been made on short-leaf and on loblolly pine, both of which may 

 be classed with long-leaf as "Southern yellow pine," and from these tests it appears that both 

 these species are inferior to the long-leaf in strength in about the ratio of their specific gravities. 

 In other words, long-leaf pine {Finns pnltistris) is about one-third stronger and heavier than any 

 other varieties of Southern yellow pine lumber found in the markets. It is altogether likely that 

 a considerable proi)ortion of the tests heretofcu-e made ou "Southern yellow pine" have been uiade 

 on one or both of these weaker varieties. 



