On the Seasoning of Hardwoods. 



351' 



It will be seen that the specimen steamed for 48 hours has lost 

 slightly more than the others. This is often the case, as tannin 

 and kino are dissolved out of the wood. 



While the drying rate is not affected, the amount of 'shrinkage is 

 seriously affected. Two typical cases are given. The timber was 

 6 in. X 1 in. messmate. The first specimen was steamed for six 

 hours, and then put oilt in the air to dry. The corresponding 

 piece was left in the air. 



steamed 

 Shrinkage [breadth - -J|in. 



(Depth . g^jin. 



The second specimen was steamed for 12 hours. 



Steamed 

 ( Breadth - " ^^in. 



Unsteamed 



Sbriukage 



I Depth 



/u" 



Unsteamed 



It will be seen that the steaming has greatly increased the amount 

 of shrinkage. The cause of this extra shrinkage is not yet known, 

 but it may be due either to the steam affecting the union of the- 

 cells or the constitution of the cell wall may be affected. 



A very interesting result was obtained by cutting a length of 6 

 in. X 1 in. timber into 10 in. lengths, and subjecting each piece 

 to a different mode of treatment before putting it out in the air 

 to dry. 



The result of one experiment is as follows : — 



Treatment 



Date 



7/11/18 



9/11/18 



19/11/18 



29/11/18 



16/12/18 



8/1/19 



28/1/19 



14/219 



The weights are given as percentages of the original weights. 

 It will be noticed that the piece treated at 10 lbs. pressure of 

 steam is the lightest. This is due to various substances l>eing dis- 

 solved out of the wood. The interesting feature of the experiment 

 lies in the fact that all the pieces have dried approximately at the 

 same rate. With the exception of the second weighing, the differ- 

 ence between any pair of weights never exceeds 3% at any 

 weighing, and in this 3% difference must be included the loss of 



In air 



2'hrs. in steam 

 at 10 lbs. pres. 



2 hrs. in steam 

 at atmos. p. 



In oven at 

 llO'c 



7o 

 100 



% 

 100 



% 

 100 





100 



97.4 



95.4 



96.8 





93.1 



89.9 



88.5 



89.2 





88.6 



86 



83 



84.3 





84.7 



80.8 



78.6 

 77.8 



77.7 



78.3 

 76 

 75.2 

 74.9 



79.5 

 77.6 

 77.9 

 76.9 





79.7 

 77.4 

 76.6 

 76.4 



