66 MISCELLANEOUS PAPERS. 



Finally, a number of analyses of different samples were made in 

 duplicate to show that the proposed method gives concordant results 

 even when some of the conditions are somewhat modified, as, for 

 example, when the volume of aqueous caustic soda added to the 

 tobacco before extraction is varied. The tabulated results follow^ : 



Field number of tobacco samples. 



75-124, 222 . 

 75-124, 202- . 

 125a-l-2... 

 ]23a-l-l... 

 123a-l-3 . . . 



DESCRIPTION OF THE METHOD. 



From these preliminary data we have been able to work out the 

 details of a very simple method for the quantitative estimation of 

 nicotine which is both .rapid and accurate and requires nothing but 

 the simplest forms of apparatus and inexpensive materials. 



The air-dried sample is pulverized by passing through a sieve con- 

 taining twenty or more Avires to the inch. For exact work the water 

 content is determined by drying over sulphuric acid for forty-eight 

 hours 1 gram of the sample on a large watch glass placed in a desic- 

 cator, while for approximate results the air-dried sample may be 

 assumed to contain 5 per cent of water. Six grams of the pulverized 

 sample are weighed into a beaker, from 3 c. c. to 5 c. c. of 5 per cent 

 aqueous caustic soda solution are added, and the mixture is stirred 

 with a steel spatula until homogeneous. The quantity of caustic soda 

 solution to be used depends on the character of the tobacco to be ana- 

 lyzed; thin, light-bodied samples, such as cigar-Avrapper tobaccos, 

 require a larger amount of the solution than do thick, heavy samples, 

 such as domestic cigar-filler types. 



The moistened samjole is next transferred to a 200 c. c. glass cylin- 

 der and 100 c. c. of the ligroin are added. The cylinder is tightly 

 stoppered and the contents thoroughly agitated for a few minutes, 

 after which the cylinder is placed in a horizontal position. This 

 insures the exposure of a maximum amount of surface of the tobacco 

 to the solvent action of the ligroin. Stout glass tubing of suitable 

 diameter and length, sealed at one end and fitted with a good soft 

 cork, serves equally as well as the cylinder for the extraction. After 

 four hours, during Avhich time the contents of the cylinder should be 

 thoroughly agitated at intervals of about thirty minutes, the latter 

 is placed in an upright position in order to allow the upper portion of 

 the gasoline to clarify. After thirty minutes or longer the extract is 

 passed through a folded filter, care being taken to first moisten the 

 filter with the clear portion of the gasoline. The extract is poured 



102— VII 



