426 THE BOOK OF THE LANDED ESTATE. 



getting to such a size as will enable us to remove the wire netting to 

 some younger plantation, to protect it. This plan has in no way inter- 

 fered with the other game on the estate, and therefore need not be 

 objected to on that account. 



SECTION 15. The Preservation of Timber. 



The very best quality of timber will begin to decay in a short time 

 when exposed to the changes of the atmosphere. Timber, if kept con- 

 stantly under water, will last a long time ; and, on the other hand, if kept 

 constantly dry, it will perhaps last nearly as long : but if exposed to the 

 weather, where it becomes wet and dry alternately, it will soon decay. 

 It therefore becomes a subject of great importance to know in what 

 manner timber may be preserved in exposed situations. 



Sulphate of copper is found to be a great preserver of wood. In the 

 south of Spain there exists an ancient copper mine which is said to date 

 from the first year of the Christian era. Some of the propwood which 

 was used in upholding the roof is still there, and in a very fair state of 

 preservation. It is charred by the crystallised sulphate of copper which 

 exists in the mine. 



When timber is decaying by dry-rot, it will be found to be connected 

 with the growth of a small plant in the wood belonging to the, tribe of 

 fungi. It feeds upon the sap, and grows very fast ; and by its rapid 

 growth, and by removing all the sap from the wood, the timber very soon 

 becomes brittle. This plant also spreads rapidly, and in a short time 

 will go over all the woodwork of a building. A good free circulation 

 of air generally prevents it from spreading. This, therefore, shows the 

 necessity of providing some means of allowing a free passage of air into 

 the roofs, floors, &c., of buildings. 



Dry-rot may be prevented, and indeed checked in its progress, by 

 boiling the wood in sulphate of iron for a few hours. 



From an experiment made at Cherbourg, it was found that the 

 woodwork of vessels could be prevented from being affected by dry- 

 rot by subjecting the timber to a slight carbonisation with common 

 coal-gas, the cost only amounting to ten cents per square yard of 

 framing and planking. 



The Kyanising system of preserving timber is to dissolve one Ib. of 

 blue vitriol (sulphate of copper) in boiling water, and then mix it with 

 five gallons of water, and have the timber steeped in the mixture for a 

 few days. 



The system of creosotiug is to subject the timber, along with dead oil, 



