When tobacco is burned, chemical changes 

 occur; the organic and other compounds are 

 decomposed. The volatile matters pass off in 

 the smoke if the combustion is complete, and 

 the mineral ash remains. In ordinary pipe or 

 other tobacco smoking, however, the combustion 

 is not complete and many decomposition pro- 

 ducts remain with the mineral ash. 



In tobacco smoke the following can usually 

 be found: Furfurol, Marsh Gas, Hydrogen 

 Sulphide, Hydrogen Cyanide, Organic Acids, 

 Phenols, Empyreumatic Oils, Pyridine, Picoline 

 Series and possibly some Nicotine. 



The ash left after complete combustion is 

 important, as much of the smoking qualities of 

 the tobacco depends on its constituents. An 

 average sample gives the following analysis (in 

 100 parts) : 



AVERAGE MINERAL CONTENTS OF TOBACCO ASH 



Potash About 27% 



Soda About 3% 



Lime About 40% 



Magnesia About 9% 



Sodium Chloride About 9% 



Sulphuric Acid About 3% 



Silica About 5% 



Lime Phosphate About 4% 



56 



