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Timber of well- matured growth should be sawn up immediately when felled, 

 and then seasoned. If logs be reduced to scantlings after partial seasoning, and 

 then further allowed to dry, they will not have such wide cracks. When boards 

 are cut green, shrinkage from loss ol water is greatest in the youngest wood. If 

 the boards are cut in planes radiating from the centre of the tree, there will be 

 extra thickness in the part near the centre. If the boards are cut in planes at 

 right angles to rays from the centre, warping takes place, the contraction being 

 strongest on the side furthest from the centre of growth. 



"When timber is sawn, it should be carefully stacked under cover to season, and 

 free access of air allowed. 



Many processes have been from time to time invented to prevent decay of tim- 

 ber, which is due to the action of fungi or bacteria. The easiest plan is to have 

 the outside charred and so prevent the attacks of microbes. For posts which are 

 to be placed in the ground, it is advantageous to slowly scorch the outside, and 

 then they may be dipped into tar, or painted with three or four coats of the same 

 material. Railway ties are improved in durability by charring. A process for the 

 preservation of timber was patented in France, by which a jet of burning gas was 

 directed by means of a tube over every portion of the surface, and this applied to 

 timber for naval purposes was said to have been successful. 



The principle of preserving timber by means of impregnation is to expel the sap 

 and afterwards to fill as far as possible the wood-cells with some antiseptic sub- 

 stance. 



Lime is one of these substances that preserve the tissues. Slacked lime is mixed 

 with water in a tank till it is quite thin. Any seasoned timber may be placed in 

 this for a number of days — about seven, if the scantling is small, such as boards, 

 up to three weeks for large timber. 



A solution of common salt may be used in the same way, but the time required 

 is only about half as long. 



Creosoted wood is timber which has been saturated with creosote in a tank. 



Colonel Haskin has lately invented in the United States a process which is 

 called " vulcanising " It consists in placing the timber by small waggon-loads in 

 an air-tight retort, and subjecting it to the high pressure of superheated air, the 

 temperature of which varies from 300° to 700.° Ordinary wood requires about 8 

 hours exposure, hardwoods from 10 to 20 hours. The wood is found not only to 

 be preserved against decay, but it has become harder and stronger. 



BOOKS ON FORESTRY. 



The following works should be consulted : — 



Manual of Forestry. By W. Schlich, Ph. D. 4 Vols. London, 1887-1395. 



Elements of Forestrv. By Franklin B. Hough. Cincinnati, 1882. 



Studies in Forestry." By J. Nisbet, D. (Ec. Oxford, 1894. 



The Forester. By James Brown, L.L.D., sixth Edition, edited by John Nisbet, 



D. (Ec. Edinburgh, 1894. 

 Timber and Timber Trees. By Thomas Laslett. London, 1875. 



