CLASSES OF CONVERTED TIMBER. 107 



expect from him. To a certain extent, however, this knowledge 

 is indispensable, especially as regards those industries which 

 obtain their wood directly from the forest, and require it in large 

 quantities. 



It is true that iron competes more and more with wood for 

 certain purposes — as for shipbuilding, agricultural implements, 

 water-pipes, telegraph-posts and railway- sleepers, where it has 

 been largely substituted for wood ; in mines, iron rails and props 

 are used ; in the construction of large bridges, woodwork is 

 entirely dispensed with, and iron instead of wooden pillars are 

 used where vertical support is required to a building. Even in 

 numerous small articles iron has been substituted for wood. 

 Yet with the constant increase in human requirements, hundreds 

 of new uses for wood are found, and the demands for high-class 

 timber therefore constantly increase whilst the area of the 

 forests decreases, so that the supply of this valuable material 

 tends to diminish.* 



The timber required for various industrial purposes does not 

 in many cases pass directly from the woodman to the artisan, 

 but generally through the intervention of a middleman, the 

 timber-merchant, who converts rough timber into pieces of 

 dimensions suitable for the requirements of the various 

 industries. In this intermediate state it is termed converted 

 or marketable timber. 



Timber may be classified according to its form, adaptability, 

 and mode of conversion, and this classification naturally precedes 

 the account of the difterent wood- industries. Thus, logs may 

 be distinguished from sawn, or cloven timber. 



2. Lof/s. 

 Logs are pieces of timber which retain the full thickness of 

 the stem, but may be more or less shortened. They are further 

 distinguished as round logs, and balks, which have been squared, 

 or are of rough prismatic shape, and are also termed sided 

 timber. 



* [A p.aper was written in the Rjviie des Eaux et Forets, December, 1894, 

 showing that in Britain, whilst tlie production of iron is as great as in all the rest 

 of Europe, yet tlie imports of timber have risen, between 1860 and 1890, by 168 

 per cent. — Tk ] 



