March, 1012.] 



219 



limbers. 



beyond three or four hours. Good re- 

 sults were obtained by treating red 

 cedar (Western U.S.) for two hours with 

 hot creosote and one hour with cold creo- 

 sote, although in this case longer treat- 

 ments sometimes gave better results. 



As regards the condition of the wood, 

 it was found that the drier the wood the 

 more readily it may be treated. The 

 absorption of preservative by green 

 timber is small and irregular, and the 

 treatment of unseasoned timber is un- 

 satisfactory in addition, on account of 

 the liability of such wood to split in 

 drying, and thus expose untreated wood 

 to decay, Where it is decided to treat 

 wood not thoroughly seasoned, the 

 temperature of the hot bath of preser- 

 vative should be high, about 215° P. to 

 230° F. Experiments carried out by the 

 Forest Service on wood which had been 

 soaked in water before seasoning showed 

 that the wood was not rendered any 

 more permeable to preservative by such 

 treatment. 



The Forest Service found that the 

 sapwood of nearly all the common 

 species of wood of the United States 

 could be successfully impregnated by 

 the open-tank process ; while, on the 

 other hand, the heartwood of many 

 species could only be successfully 

 treated by artificial pressure. The 

 absorption of creosote by poles of 

 various woods was found to be as 

 follows, 6 ft. of the butt end being 

 treated in each case :— 



Species. 



Chestnut 



White Cedar (Nor- 

 thern U. S.) 



Red Cedar (Western 

 U.S.) 



Yellow Pine ( „ 

 U. S.) 



Lodgepole Pine 



Increased Durability as a liesult of 

 Treatment. — The results of tests indicat- 

 ed that an average increased life of at 

 least three years may be expected from 

 applications of preservatives with a 

 brush. The cost of applying two coats 

 creosote to 6 ft. of pole (including cost of 

 labour) is estimated on the average at 

 about 10d., and it is computed, thers- 

 fore, that if the pole has an increase of 

 life of one to two years the cost of treat- 

 ment is amply repaid. 



The application of creosote by the 

 tank method will, it is stated, so preserve 

 the butt end of the pole that the life of 

 the pole will be the life of the top, and 



Absor- 



Penetr- 



tion. 



ation. 



per Pole. 





lb. 



in. 



21-5 



0-3 



48-4 



0-5 



39-5 



0-8 



81-4 



3-1 



34-0 



1-0 



no data as regards the life of that part 

 of the pole which is above ground are 

 possessed by the Forest Service, since 

 rep] acements are commonly made because 

 of the failure of the portion immediately 

 above and below the surface. It is 

 estimated, however, that the life of 

 chestnut is increased by six years, white 

 cedar by eight years, red cedar by ten 

 years, yellow pine by seventeen years, 

 and lodgepole pine by fifteen years. 

 The total cost of treatment with creosote 

 by the tank method of 6. ft of pole is 

 given as follows :— Chestnut, 3s. 3d.; 

 white cedar, 4s. id.; yellow pine, 6s. 9cZ,; 

 red cedar, 5s. Id.; lodgepole pine 5s. 2d.; 

 and the annual saving per pole, after 

 deducting cost of treatment, is computed 

 as follows :— Chestnut, l\d.; white cedar 

 6d.; red cedar Is. 6cZ.; yellow pine, 9s.; 

 lodgepole pine, 4s. Id. It will be noticed 

 that preservative treatment pays better 

 where the wood has very little natural 

 durability than where it has naturally 

 a large durability ; the use of the wood 

 for poles, posts gates, &c, which would 

 otherwise be unsuitable is thus rendered 

 possible. 



FORESTS AND DROUGHT. 



(From the Indian Agriculturist, 

 Vol. XXXVI., No 11, November 1, 1911.) 



We dealt several months ago with an 

 important article on the influence of 

 forests on floods, which appeared in the 

 Indian Forester. The conclusion arrived 

 at by the writer was that, whatever, 

 their effect upon the rainfall, forests do 

 unquestionably affect the violence of 

 floods and minimise the destruction 

 caused by them on steep hillsides. In 

 the current number of the same public- 

 ation appears a highly interesting con- 

 tribution dealing with " The Influence 

 of Forest on Drought," a subject of ex- 

 ceptional moment to India. The beliefs 

 of the Forest Officer who holds the tenets 

 of the European schools are described 

 at the outset. He contends that forests, 

 especially in mountainous regions, store 

 the waters that fall from the clouds, 

 preventing their too rapid surface flow, 

 minimising their evaporation; and giving 

 them gently off in the shape of perennial 

 springs and rivers with an equable flow. 

 The absorption of the rainfall into the 

 ground is facilitated by the roots of the 

 trees, which break up the soil ; and it is 

 maintained that while 6 per cent, of the 

 rainfall percolates more than two feet 

 into the soil in land bare of trees, 60 per 

 cent, does so in the case of forest lands 

 which are covered with vegetable mould. 

 Another point of importance is the fact 



