certain Vegetable Salifiable Bases. 281 



smell and action upon turmeric paper; the odour of prussic 

 acid may also be distinctly perceived ; an oily matter smelling 

 like naphtha, distils into the cool part of the tube in which the 

 experiment is made, and a very abundant carbonaceous residue 

 remains. 



The most remarkable circumstance attending this decomposi- 

 tion of cinchonia, is the entire absence of all appearance of aque- 

 ous vapour, of which I have never been able to distinguish any 

 traces, provided care had been taken to exclude air, even when 

 the products were made to pass through a considerable extent of 

 cooled tube. This led me to suspect the entire absence of oxygen 

 in this substance, an opinion which was corroborated by its total 

 want of action upon potassium, when heated with that metal in 

 naphtha: the cinchonia, under these circumstances, readily dissolves 

 in boiling naphtha, and again entirely separates as the solution 

 cools, concreting into a radiated crystallized mass, in which the 

 brilliant globules of potassium are disseminated. 



The singular and characteristic properties of these vegetable 

 alkalies, induced me to pay more attention to their ultimate ana- 

 lysis, and to endeavour to attain more accurate information re- 

 specting the nature and proportions of their elements, especially 

 as cinchonia is stated, by its discoverers, to consist of oxygen, 

 hydrogen, and carbon, and to be deficient in nitrogen*; a state- 

 ment at which I am the more surprised, since a repetition of their 

 principal experiments upon these bodies, has convinced me of the 

 extreme accuracy of their difficult researches. In these experi- 

 ments, which are always tedious and difficult, I have availed 

 myself of the forms of apparatus contrived by Dr. Prout and Mr. 

 Cooper, (Henry's Elements, ii. 165,) employing the peroxide of 

 copper as originally recommended by M. Gay-Lussac, (Ann. cle 

 Chimie, xcvi. 53,) with the precautions suggested by Dr. Ure, 

 in his valuable paper on the ultimate analysis of organic substances 

 published in the Philosophical Transactions for 1822. 



• Annates de Chimie el Physique, XV. 296. 



