Analysis of Aloes. 225 



tained by cutting transversely tbe leaves of the aloe perfo- 

 liata socotrina, placing earthen vessels underneath it to 

 receive the juice, which is thickened in the sun. 



The aloes which was made the subject of the examina- 

 tion is of a yellowish red, and semi-transparent : it pre- 

 sents, in its fracture, several yellow points which glister on 

 a red ground : reduced to powder it is a fine yellow colour : 

 it has a very bitter taste, and a smell which some persons 

 think is not disagreeable: it does not become electrical on 

 friction. 



• When exposed to a heat of 80° + of Reaumur, it be- 

 gins to soften, and then melts : on account of its being 

 easy of fusion, it is much easier to pulverize it in winter 

 than in summer. If we present a piece of it to the flame 

 of a candle, it melts with a crackling noise, and inflames. 



§ II. 50 grammes of aloes were distilled at a heat very 

 gentle at first, and incapable of decomposing it, when the 

 following products were obtained : 1st. Eight grammes of 

 water charged with an essential oil which gives aloes their 

 smell. 2d. At a greater heat there passed over 8*7 gram- 

 mes of almost colourless water, in which I found one gram- 

 me of acetic acid, but no ammonia, on adding quicklime 

 in powder to the liquor. 3d. Five grammes of a heavy red 

 oil soluble in alcohol. 4th. A great quantity of oleaginous 

 hydrogen gas and carbonic acid. 5th. There remained in 

 the retort (which had begun to melt) twenty grammes of a 

 hard charcoal very voluminous and honeycombed, which 

 retained a great quantity of hydrogen, which we saw burnt 

 by exposing it a long time in a crucible at a strong heat in 

 order to incinerate it, which was impossible : it preserved all 

 its blackness, its shining appearance, and a great hardness : 

 it had lost however 12*5, which I attribute in a great mea- 

 sure to the hydrogen. The 7*5 grammes which remained 

 did not contain any potash. This charcoal was treated 

 with muriatic acid : the filtered liquor was precipitated by 

 ammonia, which separated oxide of iron and a small quan- 

 tity of phosphate or lime : the carbonate of potash preci- 

 pitated some decigrammes of carbonate of lime. 



If we heat nitric acid on this charcoal, we obtain a small 

 quantity of tanning matter which precipitates strong glue. 



§111. Aloes in powder, bruised in a glass mortar witli cold 

 water, yielded a mass which, squeezed through the hands, 

 was tacky like turpentine. We succeeded in obtaining 

 a complete solution by adding water in successive quanti- 

 ties, but it required a great quantity ; the last portion which 

 remained to dissolve was similar to the first in point of 



Vol. 36. No. 149. Sept. 1810. P bitterness 



