THE WOOD 237 



12. Wood is ground into pulp and made into paper 

 and pulp boards with endless variety of application. 

 Wood pulp, made by chemical processes, results in cellu- 

 lose and its countless derivatives, which are capable of 

 supplying almost anything, from a shirt collar to a car 

 wheel. 



13. Distillation of wood furnishes charcoal to the smithy 

 or furnace ; vinegar to the table ; alcohol to the artisan ; 

 creosote to the wood preserver ; gas for fuel and light ; 

 tar for roof boards ; pyroligneous, oxalic, acetic, and other 

 acids, as well as acetone, paraffin, naphthalin, etc., to the 

 manufacturing chemist ; and, by a slight variation of the 

 process, lampblack to the printer and painter. 



Wood also differs from the metals in several other 

 respects. It is not fusible ; it cannot be cast ; hence, to 

 duplicate a form in wood requires the same amount of 

 effort as did the original. Changed into pulp, and still 

 more into cellulose, this drawback is largely overcome. 

 Wood cannot be welded, though, as stated before, this 

 is more than compensated by gluing; nevertheless, an 

 end-to-end junction of the kind produced in iron cannot 

 be effected. 



Wood cannot be rolled ; it must be cut into shape ; but 

 owing to its softness and cleavability this requires incompar- 

 ably less effort and equipment than the rolling of metals. 



Wood is hygroscopic ; it contains water under all ordi- 

 nary conditions, and the amount so contained varies with 



