66 TAKMANIAN TIMBERS. 



SEASONING AND SHRINKAGE. 



Rankin's "Machinery and Millwork," page 471: — 



Seasoning for carpenters, two years; for joiners, four 



yeai's, and often much longer. 

 Shrinkage 2 to 8% ^.ransverse, usually 3% ; loss of 

 weight 6 to 40%. 

 Molesworth's '' Engine rs' Pocket-book," page 113, 

 Mahogany, Walnut, or Oa k seasoning : — 



Inchps of Thickness §" i" f f" I" 1" li" 2" 0" 4" 

 Mentha of Time 12 13 14 16 20 24 30 36 46 S2 



Barlow gives the shrinkage of Oak as 3% for the butt, 5% 

 for the top, and the loss of weight as, at least, a third in 

 drying. 



T. A. Knight, in " Philosophical Transactions," vol. 107, 

 p. 269, shows that Ash and Beech cut on the back, or 

 parallel toi the rings of growth, shrank 14% of the width, and 

 warped ; while the san>e cut on the quarter, or across the 

 rings of growth, shrank 3|% of its width, and did not warp. 



Tredgold quotes Rondelet's experiments, showing that 

 ordinarily dry Fir will expand up to H% of width, and Oak 

 to 1J%, under ordinary changes in the dampness of the 

 atmosphere. 



Tasmanian timbers lose from 22% to 40% of their weight 

 in drying. The usual allowance for the shrinking of Tas- 

 manian hardwood is from half an inch to an inch to the foot, 

 or 4 to 8% ; but this is only a rough general assumption, and 

 no exact experiments have been made for the determination 

 of the shrinkage. It is known generally that it varies con- 

 siderably in the different timbers, that of Celery-top Pine 

 being the least, and that of Stringy Bark probably the 

 greatest; while, from the same kind of tree, timber grown 

 on good moist land will shrink more than that grown upon 

 poor rocky soil, and the young wood more than that of 

 matured trees. It would be very useful indeed if the per- 

 centage of shrinkage, both radially and along the rings, were 

 settled by experiment, for each kind of timber. 



With regard to seasoning (most Tasmanian timber is sold 

 uniseasoned), the practice in England is given above, but 

 after the length of time allowed for seasoning, for carpentry 

 and the rougher sorts of work, the joiners will either season 

 for several years more, or further dry the timber in a hot 

 room before using it. During the time of drying, the timber 

 is carefully stacked with numerous slats between the planks, 

 and sufficiently weighted to keep it from buckling. As has 



