Till-: m.ACK w vriLK ixinsrm. j<): 



This .shows what his previotis experiment failed to do, that 

 the younger hark on the ni)per part of the tree, besides being 

 thin and liij^hi. lias a lower percentage of tannin than the lower 

 bark. 



The lower third part of the tree contains usually more than 

 half the tanning matter obtained from the complete tree. Con- 

 se(|uently, to secure bulk of uniform grade of bark, only the 

 lower portion, say the first i2 feet ma\- be used together, leaving" 

 the balance for a lower grade. The thickness and weight of the 

 bark natttrally are less, th€ further up the tree the sample is 

 taken fn^n, and the bark on the uj^per ])ortion of a nine-year- 

 old tree is less thickness and weight than on the lower portion 

 of a three-year-old tree. This introduces an element of selec- 

 tion in grading, which so far has received little attention. While 

 the bark of young plantations which are being thinned, and 

 which is all thin bark, is easily segregated as thin bark, it is 

 doubtful if many growers separate the upper portion from the 

 lower portion of the same tree ; 32 per cent, has usually been 

 regarded as the standard for f.a.(|. bark exported, and for all 

 reasonably thick bark is easily reached. 



In grading, the thickness of the bark has been adopted as 

 the basis of classitication excei)t in the case of damaged bark, 

 and a further table in \\'illiams's report shows that this is justi- 

 fied ; that dry bark tinder 0.1 inch in thickness contains usually 

 under 30 per cent., and sometimes as low as 24 per cent., whereas 

 thicker bark is of gradually higher percentage uj) to samples 

 0.17 inch thick, yielding about 40 per cent. 



How this afi^ects even thicker bark is not shown, but in 

 view of the later developments in wattle culture and the ten- 

 dency toward thicker and more mature bark it is of great 

 interest, and should be ascertained. 



