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FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE. 

 Description of test material and rexults of plxjttcal examination. 



These particular tests can hardly settle definitely any question. Samples 1 and 2 being 

 selected stock, second growth, can not be used for comparison with samples of B, except to show 

 that for stiffness the unselected Southern stock is superior to the best Northern growth, as also in 

 resistance to endwise compression. Tiie samples 3, 4, 5, and 6 are probably more nearly compara- 

 ble to samples of B, and here we find the Southern oak very much superior, not only in stillness 

 and columnar strength, but also in ultimate cross-breaking strength, while for resistance to shock, 

 at least one sample of Southern oak is superior to three samples of forest-grown Northern, and 

 even to one of the best Northern second growth. This piece (No. 8) exhibits, altogether, qualities 

 which render the verdict tenable that Southern oak is not necessarily inferior to Northern oak in 

 any of its qualities. 



Beyond this it would not be safe to use these figures for generalizations. 



In 1888 the really first beginning in timber physics was made in the form of a preliminary 

 physical and structural examination of a set of trees representing the more important lumber pines 

 of the South and of the lake region, as well as of bald cypress. A comprehensive plan was fully 

 worked out and the mistakes of former methods were carefully avoided. In 1891 a more extensive 

 study of the four great Southern timber pines, the longleaf, Cuban, loblolly, and shortleaf, was 

 begun, and the material was at the same time collected in such a manner as to enable a detailed 

 inquiry into the relative merits of timber bled or tapped for turpentine as compared with nnbled 

 timber. 



The trees were collected by Dr. Charles Mohr, of Mobile, Ala., an acknowledged authority on 

 the botany of the region, and thus a correct identification was assured. Of each tree entire cross 

 sections as well as the intervening logs were utilized, the former being subjected to examinations 

 into their specific weight (the acknowledged indicator of many valuable technical properties), into 

 the amount of moisture contained, into the shrinkage consequent on drying, and into the struc- 

 tural peculiarities, particularly those structural features which are readily visible and may be 

 utilized in practice for purposes of timber inspection. 



The logs were sawed and tested according to definite plans in the well-equipped test laboratory 

 of the Washington University, St. Louis, Mo., under the direction of Prof. J. B. Johnson, a recog- 

 nized authority in engineering. The first series of test results are embodied in Bulletin No. 8 of 

 the division, where the strength values for the lougleaf pine are fully tabulated and discussed. So 

 eagerly was this bulletin sought by wood consumers, that an edition of 5,000 copies was exhausted 

 in a short time. 



BLED AND UNBLED PINE. 



In addition, this series of tests together with an extensive chemical analysis and physical and 

 structural examination of material from unbled and bled trees, as well as from trees bled and 

 abandoned for five years, re-enforced by an extended study of bled and unbled timber at various 

 points of manufacture, proved conclusively that the discrimination against bled timber \v;is 

 unwarranted, since the bled timber was neither distinct in appearance, behavior, nor strength. 



To avoid error in so important a matter, and also for a comparison of the three most important 

 turpentine trees the Cuban and longleaf with the loblolly pine the extensive chemical analyses 

 of Dr. M. (romberg, of the Michigan University, were repeated and extended by Mr. O. Carr, of 

 the Chemical Division of the Department of Agriculture. This series of additional chemical 



