3b2 



ACtlOJf OP NITlilC ACID ON INJDiarf. 



and oQ aloes. 



Supposed acid 

 from indigo. 



Inquiry Insti- 

 tutetl concern- 

 ing it. 



Indigo treated 

 with nitric acid. 



Products 

 ilistilled over. 



Matter in the 

 retort. 



that differed from the amcr of VVelther: and considered it 

 as a compound of niii^zc add, amer, and artificial tannin. 



6. Mr. Braconnot, in a paper on gum-resins, speaks of 

 an add, Avhich he obtained with aloes and nitric acid. He 

 remarked, (hat this acid bore some analogy to the amer of 

 indigo, and also to an orange-colonred substance, that 

 Messrs. Fourcroy and Vauqiielin had formed with muscular 

 flesh and nitric acid*. 



7. In the month of January, 1809, I resumed my exa- 

 mination of the amer of Brazil wood, in order to find how- 

 far it resembled the aloetic acid of Mr. Braconnot, when 

 Mr. Vauquelin communicated to me a letter, in which he 

 was informed, that Mr. Moretti, professor of chemistry at 

 Udina, had obtained, by distilling indigo with nitric acid, 

 an acid, that formed a detonating compound with potash, 

 soda, the oxides of iron, lead, silver, &c. It was added, 

 that Mr. Moretti considered it as a new acid, because it 

 could not be confounded with the benzoic, which Messrs. 

 Fourcroy and Vauquelin said they had formed with indigo. 

 Mr. Vauquelin was desirous, that I should repeat these ex- 

 periments; and at the same time requested me to examine, 

 whether these acid and detonating products did not owe 

 their properties to some nitric acid, which they retained in 

 combination. 



§ II. 8. Into a retort I poured four parts of nitric acid 

 at 32« [1*283] diluted with four parts of water. A re- 

 ceiver being fitted to it, I placed it on a moderately warm 

 sand heat, and added gradually two parts of Guatimala 

 indigo coarsely pounded. The mixture grew hot, and a 

 quantity of nitrous vapours, carbonic acid, &c., was evolved. 

 Fearing the action would become too violent, I removed 

 the apparatus to a cold sand bath, and left the substances 

 to themselves for four and twenty hours. 



9. During this time nitric acid, prussic acid, and a small 

 quantity of yellow bitter matter, had passed into the re- 

 ceiver. 



10. The liquor, that remained in the retort, was of a 

 reddish yellow, and two concrete substances floated on it. 



* See Journal, vol. xxvii, p. 361. 



The 



