272 TIMBER 



at all uncommon to stack Baltic or pitch pine logs for three 

 or four months prior to treating them with creosote. 



The seasoning of timber causes a good deal of reduction 

 in its weight. 



If a log of timber be dried for a time and then cut across 

 in different places, it will be found that the amount of 

 moisture in the wood increases from the ends, showing that 

 for some distance the moisture evaporates that way, being 

 the easiest way out, but the drying, especially in large logs, 

 takes place almost wholly through the faces, and, as a rule, is 

 a very slow operation (see page 304). If the log be largely 

 heartwood, or if the proportion of sap be fairly uniform, it 

 will dry more rapidly. 



Timber can be reduced in weight by boiling, and it is a 

 carious fact that placed in live steam it will lose weight 

 rapidly, whilst saturated steam has quite the contrary 

 effect upon it. 



Timber after being cut should be stacked in layers, each 

 piece and layer being kept separate so as to allow a free 

 circulation of air, and the stack should rest on bearers or 

 supports which will keep it at least 12 inches above the 

 ground. This should be done in covered sheds if possible, 

 in fact for all planks and battens under 3 inches thick 

 covered sheds are necessary, but, as a rule, large-sized 

 timber is seasoned in the open (see Figs. 37 and 38). 



On the Continent, when timber is not placed under sheds, 

 as for instance with railway sleepers, it is often given a slant 

 longitudinally so as to allow the wet to escape more easily. 



Fig. 39 shows a common method of seasoning planks in 

 timber sheds, but in some of the White Sea sawmills it is 

 stacked with many of the planks on edge, which gives the 

 timber an excellent chance of drying, but this requires a 

 great deal more space. Some have tried and recom- 

 mended the placing of timber on end, but this has no 



