78 



TIIK AVniTE PINK. 

 Average slrmijlh of llie wood of II hilr I'iiie of diffeiinl tree ut I .' per icnl iiioiHlure. 



a InBiifliciniit (latii for a fair avorage. 



In tlie above table tlie data for frees loi Ik 1 Hi arc insullicicnl. Ilotli iiiiifciial and test.s for 

 trees (!01 to GOO wen^ salislactory in every respetst, and tlii' results, tlicrct'oie. of far {jreater value 

 tlian tlio.se fi.r trees 1(»1 to 110. 



Ill keeping' with its },nealer weight, the wood of the butt logs is slightly stronger than that of 

 the top logs, and there is generally a regular dillerence hetwoeii dilVeicnt parts of the same cross 

 section, the center, as apjieais usual in jiiiu', being the weakest, the heavier intermediate portion 

 the strongest, an<l the jicripheral part lying between the two. 



For a more careful study of this relation, tests were made of a set of 2 by 2 iiudi sticks cut out 

 of one log from eacli of three trees, in such a manner that the centers of the, logs formed mie set, 

 the part midway from center to bark another set, and the outer portion of the logs a third or outer 

 set, the latter two being all quarter-sawed pieces. Tiie tests fiiriii.slied the tbllowiug average 

 results: 



Sirviiijlli ill' : III) : pUces at 1'.' per cent mointiirr. 



K ind of tfst. 



True No. 001. 



C'onii»rr8«ioii oiulwiai' 



IWtiiitiii;; to rcliitivo clastic limit 



Itciiilint; tt> nipt tire 



ModiiluH (if clustieity (l.ouD iiiiiinilH}. 



Pounds per 

 sit. ill. 

 0.710 



7. 900 

 », 300 

 1,306 



Tree No. 602. Tree No. 603. 



Pounds per 

 sq. in. 

 0,890 



7. «70 

 !", 1130 

 1,291 



Pounds per 

 Mf. in. 

 B. 340 



7, 800 

 0. 340 

 1,285 



It is apparent from the ab()ve that the! perfect <iiiarter-sawed material conlirmed the other 

 test results in showing the great similarity of tiie wood of tlie.se three trees, it also .shows, how- 

 ever, that the etfect of defects in an iinselected lot reduces the strength values markedly in this 

 species. 



Arranging the results according to the position of the test jiieces in the log, it is found that in 

 compression endwise the strength was: Center pieces, 5,"i20 pounds, or 78 per cent; intermediate, 

 7,000 pound.s, or TOO ]ier cent; outside pic(!es, «,(;.S0 ])ounds, or it.") jier cent; showing that the 

 heart pieces, as has been found in other conifers, are always the weakest, thus verifying the results 

 of the general series. The slight decrease from the intermediate to the outside jiieces is in keeping 

 with the smaller weight of the latter and need not be a.scribed to the fact that these pieces con- 

 tained small proportions of .sapwood. As might be expected, the uniformity of results in this 

 properly selected and juepared material was greater than in the ordinary series. Of 58 tests, all 

 fell within L'.") per cent of the average strength and 7(> per cent within 10 per cent of the average. 



In connection with a general study into the maximum uniformity of wood, three scantlings of 

 White Pine, with an average specilic gravity of about O.^U and an average com|)iessive strength 

 at 8 per cent moisture of 1,900 pounds, were examined, two being tested air dry (8 per cent) and 



