THJ^; CJARDEN AND FIELD. 



Norember, 1913 



The Practical Use of 

 Timber. 



Although the following notes 

 refer more particularlv to western 

 (N'.S.W.) timbers, the principles 

 enunciated applv nevertheless 

 equally to the use of timbers from 

 other districts. Before entering 

 upon the subject we will give an 

 ek^mentarv description of the struc- 

 ture of timber. 



All trees that provide us with 

 timber are outward growing trees 

 — that is to say, they increase in 

 girth by developing successive 

 layers round the trunk next to the 

 bark. Each year gerterallv adds 

 one of the layers or rings, and 



consequently thev are called 

 " annual rings." In addition to 

 the annual rings, trees have me- 

 dullary rays, which are thin and 

 generally broken lines, radiating 

 from, the centre, or pith, to the 

 bark, and \-ice \*ersa. ' These rays 

 are not ver}' apparent in some 

 tree's, but in dry express pine they 

 are easily se>zn. Cabinet m-akers 

 call these rays the "silver grain." 



The trunks and branches of trees 

 consist of two kinds of wood — the 

 hard, dead heartwood, or dura, 

 men, and the soft sapwood, or al- 

 burnum. The latter is much 

 lighter in colour than the former. 



The bark consists of an outer 

 and inner layer. 



It is through the sapwood that 

 the root-sap is carried up to the 

 leaves. Here 'chemical changes 

 take place with the carbon that 

 has been abstracted from the car- 

 bon dioxide of the air, which has 

 found its wav into the leaves by 

 means of the breathino- pores or 

 stomata. After the various changes 

 have taken place the " food sap " 

 returns by means of the inner bark 

 and passes through the medullary 

 ravs to noiirish the tree. 



Heartwood is much stronger and 

 more durable than sapwood, and 

 the oxvter portion of the heart- 

 wood is stronger than that near 

 the centre, or pith, more particu- 

 larlv if the wood is " pipev," be- 

 cause then it has been subjected to 

 decav and is very brittle. 



Old wood is stronger, thouijh 

 lighter, than voung wood. The 

 strenp-th of t mber is influenced bv 

 the quality of soil on which it 

 grows. Kvenness of erain in the 

 annual rings denotes strouT wood. 

 Tvocalities subject to droughts 

 produce faulty timber. 



By strength of wood we mean 

 the re.sistance it offers to force 

 acting at risrht antrles to its 

 erain. This is called "transverse 

 strength." 



It must be patent to all that 

 where the strongest pnrts of tim. 

 bcr are preserved the structure 

 built would have a much longer 

 life than where the weaker tissues 

 are made to stand the strain. 



For stockyards, stables. huts, 

 and the like, cvpress pine (Callitris 

 sp.) timber is generaJlv used in 

 this district, because it is practi- 

 callv the only timber of any sir.e, 

 and is much easier split and work- 

 ed than the eucalypts and acacia. 



Cypress pine is verv fissile, but 

 will stand veJry little transverse 



strain ; and therefore, when using 

 it, knowing of its weakness, work- 

 ers should aim at conser\T.ng the 

 strength in every possible way. 

 Anyone famiHar with pine used in 

 stockyards knows that the rails 

 most frequently break at or near 

 the middle and at the tenon, which 

 fits the moTtise of the post. When 

 pirFe saplings are used as rails the 

 posts shoiiid be close together to 

 lessen the strain when stock 

 bump against the rails. Little or 

 nothing but the bark should be 

 removed from young pine in mak- 

 ing a tenon, because the young 

 wood is much weaker than that 

 from' mature trees, and by re- 

 moving the harder heartwood of 

 an already weak timber the 

 strength and durability is very 

 materially lessened. — Agricultural 

 Gazette of N.S.W. 



'■ ♦ 



Separating Temperatures. 



In a recent issue of Hoard's 

 Dairyman, Mr. J. H. Monrad, of 

 Denmark, gives some interesting 

 notes upon the effect ol tempera- 

 ture on the work of the cream 

 separator. In Denmark cream and 

 skim milk must, under the law, 

 be heated to at least 176 degrees 

 Fahr. for pasteurizing, and thus 

 the milk can be separated at a high 

 temperature if this is desirable. 

 As a fact, the normal separating 

 temperature in Denm.ark may be 

 placed at about 131 degrees. Ex- 

 periments at the Royal agricultur- 

 al laboratory in igio showed, 

 however, that this temperature 

 was little superior to 95 degrees, 

 which is about the temper'ature of 

 freshlv-drawn milk, the difference 

 amounting to only .006 per cent, 

 iu favour of the warmer milk. 

 The difference, however,^ became 

 much more pronounced when the 

 temperature was allowed to drop 

 below 95 degrees, and G-erman ex- 

 periments are quoted 'showing 

 that at S6 degrees there was 2 per 

 cent., and at 50 d*egrees there was 

 6 per cent. left. Altoorether, the 

 data quoted show that freshly- 

 drawn milk is warm ' enough for 

 practical purpos?s, but that when 

 the milk has bpf-n cooled by stand- 

 ing, the work of the separator is 

 decidedly less efficient. 



T absolutely refuse to take second 

 place with any remedy (no matter 

 what nricel for healing Bums, 

 Boils, Sor*>s, Cuts, etc., or Bron- 

 chitis in Children. 



(Signed) BATKS' SALVE. 



CURLEW BRANDY. 



For years the Only llranily u.twJ 

 in the Adelaide Hospital. 



Solo Ag«nti — 



DOWNER A 00. 



Win* and Spirit Merchant* and 

 Aeratod Water Manufacturers. 



43 W.WIMOTTTTT ST., CITV. 



