Seasoning of Wood. 



141 



68. Effect of Seasoning of 



K ounu 'ii mb er, showing 



570. Seasoning tends to secure the durability of wood not ex- 

 posed to the weather, cr in contact with the earth, or with damp 

 walls, if sufficient ventilation is allowed. The presence of moisture, 

 and especially of the starch, sugar, and albumen of the sap in wood, 

 tends to hasten fermentation and decay. If these are partly dis- 

 solved out by placing the freshly cut timber in running water, it 

 dry s more readily. Seasoning by smoking has the effect of increas- 

 ing the durability of wood, by charging it with creosote, but this is 

 corrosive to iron, and should not be used in contact with it. 



571. In the process of seasoning, wood tends to shrink, from the 

 contraction of the tissues as they become dry. 



As there is more moisture and less wood fiber 

 in the outer layers, the contraction is greatest 

 toward the outside, as shown in the annexed 

 engraving. The process takes place more 

 slowly, and with less cracking in winter. It is 

 still further improved by delaying the drying, 



vhinli rnnv KP rlnnA Kv rlipi'ncr in tliP clinrlp 



-\vnicn may be done Dy placing m the snacie, 

 where the air circulates freely between the 

 pieces, but it should not be exposed to the dry- 

 ing winds. 



572. It is desirable to prevent the cracking of timber at the ends, 

 by which means a loss is suffered in the more valuable kinds. This 

 may be prevented in a great degree, by pasting heavy paper over 

 the end, or by painting or washing with diluted muriatic acid, neu- 

 tralized with lime. 



573. If there be nothing at hand better, the timbers may be lightly 

 shaded from the sun by branches of trees or 



any other slight covering, where it is desirable 



to prevent deep crevices from being formed. 



Shrinkage tends to distort timber that is dressed 



green, as shown in the annexed cut, and un- 



less the center of growth is in the center of 



the piece, it will need to be dressed over again 



to secure a true form. Boards and plank whenc9. Tendency to Distor- 



cut green will warp from this cause, the contrac- by ShriS^? 



tion being strongest on the side fur- 



therest from the center of growth, and 



least in the direction of the medul- 



70. Tendency to Warp by Contraction 

 rays. nearest the Ontside of the Tree. 



