356 ORGANIC CHEMISTRY. 



896. USE OP GUN-COTTON, Gun-cotton. 



What is said 



of Us proper- is not likely, for several reasons, to super- 

 cede gun-powder, for use in fire-arms. It 

 is much more expensive, and so suddenly explosive as 

 often to burst the barrels in which it is fired. Its ex- 

 plosive force depends, like that of gun-powder, on a 

 sudden combustion throughout its whole substance, 

 and consequent evolution of a large volume of mixed 

 gases and vapor. Of these, carbonic acid, nitrogen, and 

 aqueous vapor are the principal. 



897. GUN-COTTON SOLUTION COLLODI- 



What in collo- 

 dion ? How is ON. Gun-cotton dissolves in ether, form- 

 ing a syrupy liquid, which, on evapora- 

 tion, leaves behind a transparent, tenacious film. It is 

 used, to some extent, in place of ordinary court-plaster, 

 for covering wounds and protecting them from the air. 



Howmay W ood 898 ' W D CONVERTED INTO SUGAR. 



be converted Wood may be converted into sugar, by caus- 

 ing it to combine, chemically, with four ad- 

 ditional molecules of water. This addition gives it the 

 precise composition and properties of grape sugar, and, 

 in fact, converts it into that substance. Poplar wood is 

 found best suited for the purpose, and can be made to 

 yield four-fifths its weight. To effect the conversion, 

 the wood is first reduced to saw-dust, then moistened 

 with somewhat more than its own weight of oil of vit- 

 riol, and left to stand for twelve hours. Being subse- 

 quently pounded in a mortar, the nearly dry material 

 becomes liquid. It is then boiled with addition of 

 water, and the transformation is completed. It only 

 remains to remove the sulphuric acid, and evaporate 



