AVALYSI8 OF ALOES. ^Q] 



The preceding descriptioH differs in several respects from Mistake of 

 that of Mr. Karsten, who no doubt had but few specimens ^*'^^'^" 

 to examine. In saying, that its colour externally was ^ 



grayish black, he was probably misled by some specimens 

 covered with a pellicle of chalcedony, which in fact have 

 this colour. 



VII. 



Comparative Analysis of Gum-Resins: By Mr. Henry 

 BiiAGONNOT, Professor of Natural Hist orj/, Sfc* 



J. HE substances I purpose to examine are interesting, Gum-resins 

 have hitherto been considered only in a few points of view, ? ^* s*^ ^'j^'^t of 



•' '^ ' inquiiy. 



^nd the labours of Boulduc, Geoffroy, Neumann, and 

 Carthcuser, leave much to be desired with respect to them. 

 Besides, the great progress made by chemistry aince their 

 iiime demands a fresh examination of the gummy-resinous 

 ^ipiubstances, of which modern chemists have taken but a 

 x;ursory view ; and this emboldens me to consider in a new 

 j^ght the concrete juices of vegetables, availing myself of 

 ^Jthe present state of chemical science. If I have attempted 

 an undertaking beyond my strength, at least I will not 

 have to reproach myself with not having done my best to 

 merit the approbation of the learned. At present I shall 

 J)ring forward only a part of my labours, intending soon 

 to complete them. 



Article I. Analysis of Aloes. 



§ I. The aloes, that was the subject of this examination, Aloes described. 

 was of a yellowish red, and semitransparent; in its fracture 

 it exhibited several yellow specks shining on a red ground; 

 reduced to powder it was of a fine yellow colour; it had a 

 very bitter taste, and a smell not disagreeable to some peo- 

 ple. It did not become electric by friction. 



Exposed to a heat of 80° R. [212° F.] it first softens, Anion of heat 

 and then melts. This fusibility is the cause of its being '^"^*'' 



* Abridged from Ann. de Chim. vol. LXVITI, p. 19. The 

 paper was read to the Academy of Sciences at Nancy the 14tli of 

 Jan. 1S08. 



much 



