7O Cellulose 



seen that, although the proportions of gaseous products vary 

 considerably, the ratio of CO 2 to CO shows a general con- 

 cordance, and is approximately that of their molecular weights. 

 There is, therefore, ground for supposing that the disruption of 

 the molecules is preceded by the accumulation of oxygen in 

 the one direction, and of hydrogen in the other direction, 

 within the molecule, reaching a maximum with the formation 



f O 



of a group prC>O, which is then split off explosively, and at 



the same time resolved. The complementary phenomenon is 

 the further condensation of the residues to form the * pseudo- 

 carbon,' or charcoal, in which the carbon is accumulated 

 relatively to the hydrogen and oxygen, and contains ap- 

 proximately two-thirds of the carbon of the original cellulose. 



The constitution of the carbonaceous residues of the process 

 or charcoals is at present problematical. The subject has been 

 discussed by the authors, in a paper on the Pseudocarbons (Phil. 

 Mag. May 1882), a name suggested for the designation of this group 

 of compounds which may be taken to include the coal series. This 

 paper contains a general discussion of the composition of these 

 substances chiefly devoted to showing that they are not to be 

 regarded as containing * free ' carbon. They are, in fact, C.H.O 

 compounds, and yield derivatives with chlorine, nitric acid, and 

 sulphuric acid, similar to those obtained by Sestini from the bromic 

 or ulmic group of compounds. 



Synthesis of Cellulose. With a large number of 

 carbon compounds it is possible to dissect them molecularly 

 in such a way that the component groups or residues may be 

 put together and the original molecule or compound recon- 

 stituted. This is the ordinary history of the synthesis of these 

 compounds, of which the modern science furnishes innumerable 

 instances. In the case of cellulose only one process has been 

 described which may be considered as a constitutional dissec- 

 tion, and that is, the breaking down of the molecule by sulphuric 



