THE JOURNAL 



OF THE 



BOARD OF AGRICULTURE 



Vol, XVIII. No. 4. 



JULY, 1911. 



INCREASING THE DURABILITY OF TIMBER. 

 William Somerville, M.A., D.Sc. 



Sibthorpian Professor of Rural Economy, Oxford. 



It has long been recognised that much may be done to 

 increase the durability of timber. It is for this purpose that 

 outside woodwork is often painted, though incidentally the 

 appearance of the object so treated may also be improved. 

 The intention of applying a coat of paint or similar material 

 is to exclude moisture, because it is known that decay of 

 wood— as of all other vegetable substances — is in some way 

 connected with the presence of water. In a sense this is 

 only half a truth, because wood may be saturated with water 

 and yet may show great resistance to decay. This is illus- 

 trated by the fact that the woodwork of Roman bridges has 

 I been removed from the beds of rivers, in a comparatively sound 

 condition after immersion for nearly 2,000 years. Similarly 

 in the case of peat bogs, from which the trunks of trees in a 

 perfectly sound condition are removed after having lain for 

 I many thousands of years. We have another example of the 

 j preservation of wood through the agency of water in the 

 so-called " ponds" that one sees alongside many tidal rivers, 

 where imported timber is often kept for years in a much 

 better state than would be the case were it piled on shore, 

 j The fact is that whereas moisture is a necessary condition 

 of decay, it cannot act in this way unless assisted by air, 

 ' and air is practically absent in wood that is saturated with 

 water, as in the piles of bridges, in bog-oak, and in timber im- 

 mersed in tidal "ponds." Water and air are both essential 



