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% REMARKS ON SOME OF THE SUBSTANCES FOUND IN TOBACCO _Nicotine_ Of all the substances found in tobacco, nicotine is the most important. Nicotine in the pure state is a colorless liquid having a specific gravity of 1.027. It is an organic base having the chemical formula C{10}H{14}N{2}. It is extremely acid and burning to the taste, and is a virulent poison. It easily volatilizes; is inflammable, and is soluble in water, alcohol, ether and some fixed oils. Nicotine has the characteristic peculiar odor of tobacco. The amount of nicotine in tobacco is said to depend on the nature of the soil in which it is grown; rich, heavy soils and strong nitrogenous manuring favor the production of a large nicotine content; and light, sandy soils the opposite. Moreover the nicotine content depends on the age and development of the plant. An investigation by Chuard and Mellet showed nicotine contents of leaves: In young plants 7 weeks old contained .0324% In plants 10 weeks old contained .0447% In plants 13 weeks old contained .4989% In plants 19 weeks old contained .9202% The longer the plant is permitted to grow the larger will be its nicotine content. Schlössing has made a similar investigation and found that in the same plant the nicotine content varies from 0.79% when young to 4.32% when fully matured. Most nicotine is found in the ribs and veins. H. B. Cox (_American Druggist_ V. 24, 1894, p. 95) investigated the nicotine contents of various manufactured tobaccos. These were not "proprietary tobaccos" but samples obtained from different sources at random. His results are given here: NICOTINE CONTENTS OF DIFFERENT TOBACCOS _Nicotine_