46 



AMERICAN MUSEUM GUIDE LEAFLETS 



FIG. 38. "OPEN-TANK METHOD" IN WOOD PRESERVATION 



Experiments have proved that treatment of wood in a preservative fluid (coal- 

 tar creosote i makes it resist decay in moist situations. This fact will revolutionize 

 the market for posts, poles and railway ties 



Unseasoned 



Seasoned 



FIG. 39. COMPARATIVE SATURATION IN UNSEASONED AND SEASONED POLES 



A partial vacuum must be created in the wood ln-fore the preservative fluid can 

 l>e forced in; and since air can he expelled much more readily than water, seasoned 

 timber is more effectively treated than green 



