52* AUXILIARY FOREST INDUSTRIES. 



When coniferous wood is dried slowly, the percentage of 

 heat-giving rosin increases at the expense of the volatile 

 turpentine. As regards the relative increase in heating-power 

 by the carbonization of wood, see the next chapter. 



In order to reduce the combustibility of wood and produce 

 so-called uninflammable wood, the following substances may be 

 smeared on it, or injected. Lime-water, clay in a saturated 

 potash solution painted on the wood in several coats. Alum, 

 soluble-glass, five to six coatings. Wolframate of soda is 

 effective, but costly. Hot solutions of green vitriol and iron. 

 Kyanised wood also is said to be uninflammable. The best 

 methods are, however, commercial secrets. 



[Wood processed by the Non-inflammable Wood Syndicate, 

 2, Army and Navy Mansions, Victoria Street, London, was tried 

 recently on the site of the old Millbank Prison and two con- 

 structions erected of injected and unirijected wood ; all efforts 

 to burn the former failed. The substance used is colourless 

 and harmless, it does not rot, does not affect the strength of 

 the wood, but adds slightly to its sp. weight. It is difficult to 

 distinguish the wood which has been injected, which is to a 

 large extent protected from being worm-eaten and from dry 

 rot. The action of tools on the wood is not rendered 

 more difficult. The wood is used extensively in America and 

 Japan ; also for the British Navy and South Kensington 

 Museum. Tr.] 



Artificial wood. Soft and plastic substances resembling 

 wood are in demand to fill in defective places in valuable wooden 

 articles. The less valuable articles are filled in with putty. 

 Instead of putty the following substances are used : glue, saw- 

 dust and chalk, lime and flour, lime-water and soluble glass. 

 Softened cellulose mixed with starch or flour can be made 

 into tabular shape, and in time becomes as hard as a bone. 

 It may be pressed into shape between heated and embossing- 

 pnissos. Jf a thin sheet of veneer is placed between the 

 artificial wood and the press, the pressed article appears to be 

 carved out of valuable wood. Caustic soda or rosin may be 

 mixed with the preparation to increase its durability. 



Wood-wool under powerful compression yields a homo- 

 geneous, rigid mass. Artificial kindling fuel is made of wood 



