10 
N. C. AGRICULTURAL EXPERIMENT STATION. 
cylinder 2 to 2J inches in diameter and 15 inches long, having the 
ends contracted so as to receive rubber -stoppers. This is clamped 
in a retort stand at an angle of about 45°; the lower end is con¬ 
nected with a glass tube, which dips in a jar of water. In the 
upper end is inserted a rubber stopper with two holes. One hole is 
connected by a glass tube with a d stillation flask. A glass tube 
passes through the other hole, which is connected with a Kjeldahl 
eopdenser on the outer end, while the inner is attached by means of 
a rubber stopper, with a glass cylinder about 6 inches long and 11 - 
inches in diameter, having the ends slightly contracted. Three to 
five grams of fint ly pulverized tobacco are wet with a few c. c. water, 
to which a little finely pulverized tartaric acid has been mixed. 
Tt us is placed in the inner cylinder between two layers of loose cot¬ 
ton wool, or, better, glass wool. The distillation flask is now partly 
filled with water and boiled until the distillate is no lunger acid. 
Twenty to thirty minutes is usually long enough to separate all the 
acid. The steam passes from the flask into the outer cylinder, then 
through the material in the small cvlinder to the condenser, carrv- 
mg the acetic acid with it. It is here condensed and collected in 
distilled water, allowing the lower end of the condenser to dip in 
the wafer The distillation having been completed, the acetic acid 
is determined with if standard alkali, using phenolthaline as an 
indicator. The outer cylinder plays a very important part in this 
determination, as it keeps the inner tube the same temperature on 
the outside as inside, thus preventing the steam from condensing 
while passing through the tobacco. The steam which is condensed 
in the outer tube is collected in the jar of water at the lower end. 
Oxalic , Citric , and Malic Acids .—The solution of these acids and 
their salts in tobacco could be obtained with acidified water or 
alcohol, but both these mediums dissolve, also, other substances from 
which the separation of the acids is very difficult. It is, therefore, 
desirable that the exhaustion be cbnducted with ether, which, in 
general, dissolves neither mineral salts nor albuminous sub¬ 
stances. The employment of ether requires that the organic 
acids he liberated by the use of some stronger acid, as, for 
example, sulphuric acid. Examine first the ash of the substance, 
so that the minimum amount of sulphuric acid can be calcula¬ 
ted, which the bases, not combined with mineral acid, require. 
The ash of tobacco, for instance, may contain 60 per cent, carbonate 
of lime, 10 per cent, carbonate of potash and 5 per cent, carbonate 
of magnesia. This would require 64 per cent. SO 3 . If, therefore, 
we have 10 grams of substance for the extraction, the ash will weigh 
2 grams, and will require a minimum of 1.3 gr. SO 3 . To insure the 
freeing of the organic acids it is customary to use double the mini¬ 
mum amount, or, in this case, 2.6 gr. of SO 3 . Care must be observed 
not to use more than this proportion, as it might be carried over 
with the ether, and would cause trouble in the different determina¬ 
tions. After the sulphuric acid is diluted with four to five times its 
