28 Prof. Hare on the Reaction of the Essential Oils 



benzoate, &c. from falling, but not enough to cause the for- 

 mation of the double salt. A crystalline precipitate, indeed, 

 fell, but it was only oxalate, with a few flakes of the double 

 salt. After drying at 212 it weighed 23*16 grs. and lost when 

 heated to redness 26*85 per cent. Pure dry oxalate contains 

 24'*68 per cent, of acid; and 28*16 grs. of oxalate are equiva- 

 lent to o'71 of anhydrous acid, very nearly the quantity em- 

 ployed. Some time must be allowed for the perfect deposition 

 of the whole of the oxalate or of its double salt. 



From these experiments it appears that by simply acidify- 

 ing strongly with nitric acid, the oxalic may be separated 

 almost completely from solutions containing any of the other 

 organic acids above enumerated, and its quantity determined 

 with considerable accuracy. 



The utility of this process in separating the oxalic acid, 

 formed so largely in the preparation of the indigotic and 

 carbazotic acids and other highly oxidized compounds, need 

 not be pointed out, nor the means it affords us of estimating 

 quantitatively the nature of the changes produced on organized 

 bodies by the action of oxidizing agents. 



Durham, May 29, 1838. 



VII. Of the Reaction of the Essential Oils "isoith Sulphurous 

 Acid, as evolved in union with jSither in the Process of 

 jEtherificationy or otherwise. By R. Hake, M.D., Professor 

 of Chemistry in the University of Pennsylvania'^. 



IITAVING mixed and subjected to distillation two ounces 

 ^-*^ of oil of turpentine, four ounces of alcohol and eight 

 ounces of sulphuric acid, a yellow liquid came over, having 

 all the appearance of that which is obtained in the process 

 for making oil of wine, described in a preceding article. 

 On removing, by means of ammonia, the sulphurous acid ex- 

 isting in the liquid, and driving off the aether by heat, a liquid 

 remained, which differed from oil of turpentine in taste and 

 smell, although a resemblance might still be traced. This 

 liquid was without any sensible action on potassium, which 

 continued bright in it for many weeks. It proved, on ex- 

 amination, to contain a small quantity of sulphuric acid. I 

 ascertained, afterwards, that in order to produce these results, 

 it was sufficient to pour oil of turpentine on the mass which 

 remains after the termination of the ordinary operation for 

 obtaining aether, and apply heat. Subsequently it was ob- 

 served that when the sulphurous aether was removed by heat 



• From the Transactions of the American Philosophical Society, N.S. 

 vol, v. 



