282 Reaction of the Essential Oils with Sulphurous Acid. 



heat or evaporation, without the use of the ammonia, the proportion 

 of sulphuric acid in the remaining oil was much greater. 



By subjecting to the same process several essential oils, I suc- 

 ceeded in obtaining as many liquids to which the above remarks 

 were equally applicable. With some of the oils, however, similar 

 results were, by this method, either totally or partially unattainable, 

 in consequence of their reaction with the sulphuric acid being so 

 energetic as to cause their decomposition before any distillation 

 could take place. No product can be obtained by distillation with 

 sulphuric acid and alcohol from the oil of cinnamon obtained from 

 cassia. From the oils of sassafras and cloves, but little can be pro- 

 cured. 



However, in one instance, by previously mixing the oil of sassafras 

 with the alcohol, in the manner described in the account given of 

 the first experiment with the oil of turpentine, I succeeded in obtain- 

 ing, in addition to a small quantity of the heavy liquid containing 

 sulphuric acid, a minute quantity of a lighter one, devoid of that 

 acid, which burned without smoke, was insoluble in water, and very 

 fluid. I am disposed to consider the liquid thus procured as a hy- 

 drate of sassafras oil, or sassafreine, as I would call it, being analo- 

 gous to hydric ether. 



The oil of sassafras, whether isolated or in combination, possesses 

 a remarkable property, which, I believe, has not attracted sufficient 

 observation ; I mean that of producing an intense crimson color, 

 when added, even in a very minute quantity, to concentrated sul- 

 phuric acid. 



One drop of oil of sassafras imparted a striking color to forty-eight 

 ounce measures of sulphuric acid, and appeared perceptible when 

 it formed less than a five millionth part. This property was com- 

 pletely retained by the lighter liquid above described as procured 

 from oil of sassafras. 



I subsequently observed, that when sulphurous acid, whether in 

 the form of sulphurous ether, in that of a gas, or when in union with 

 water, was brought into contact with any of the essential oils (inclu- 

 ding kreosote,) which were subjected to the experiment, . they ac- 

 quired a yellow color, and a strong smell of this acid. 



In the case of the yellow compound thus obtained from any of the 

 essential oils which I have tried, if the sulphurous acid be removed 

 by heat, the oil, by analysis, will be found to yield sulphuric acid. 

 That some acid of sulphur remains in union must be evident, since 



