Is There a Wood Famine Coming? 51 



graph poles can be saved from quick decay by 

 what is called the " creosote process." When a 

 fragment of very thin shaving Is seen by the aid 

 of a microscope we learn that wood Is like a hon- 

 eycomb : It is a mass of little cells. In freshly 

 hewn timber these cells are filled with air and sap. 



From V. S. Forest Circular No. 111. 



Fig. 17. View in a Pennsylvania coal mine, showing the great amount of 

 timber that is used. 



By the creosote process the air and moisture are 

 drawn out of the wood cells, and then creosote 

 Is forced into them. But after awhile, in the mine- 

 damp, this creosote soaks out of the wood, and 

 then decay begins and new timber must replace the 

 old. 



In some cases mine roofs have been supported 

 by iron girders, or by broken rock. One great 



