352 Compatative Analysis of the Gum Resins. 
a very great quantity of brown empyreumatic oil, anda little 
aqueous acid liquid. These products did not in any percep- 
tible degree exhalé ammonia with lime: nevertheless, on 
adding a little nitric acid to the mixture, slight white va- 
pours were exhibited, which seemed to indicate the presence 
of volatile alkali. There remained in the retort a compact 
charcoal of the weight of 2°5 grammes, which left after its 
incineration 6°55 grammes of ashes, composed of five centi- 
grammes of potash partly saturated by the sulphuric, mu- 
riatic, and carbonic acids, and six centigrammes of phos- 
phate of lime; the rest was carbonate of lime, which forms 
the greater part of these ashes, 
§ LIT. A. Twenty-five grammes in powder were treated 
with alcohol and filtered: there remained on the filter an 
abundant whitish matter, which, when well washed in al- 
cohol and dried, weighed nine grammes. 
B. Vhese nine grammes of parts which were insoluble in 
alcohol were dissolved. in boiling water, with the exception 
of a soft grayish substance, of a gummy appearance, and of 
the weight of 173 grammes, After its desiccation, it burned 
with a flame and produced a greenis | resinous. matter on 
treating it with nitric acid, which might lead us to suspect 
that some resin had escaped perbaps, from the action of the 
alcohol, although I took great care to wash the residue with 
boiling spirits of wine, 
C. The aqueovs solution B, after having been filtered, 
produced by evaporation 7:5 grammes of a gum having the 
following properties, . ig f 
1. This gum (which had been considered as the extractive 
part by the ancients, although it had no such appearance) 
was of a yellowish transparency, and had a faint taste. 
2. ft was easily dissolved: an water without leaving any 
residue, Ae: sp ie 
3. When exposed to the fire,, it burnt with little flame, 
and left white ashes formed in a great measure of carbonate 
of lime. 
4. Its solution in water did not redden turnsole tincture. 
5. The oxalate of potash forms a precipitate in the so- 
lution of this gum. } 
6. The acetate of lead does not produce any perceptible 
change in it; but the nitrate, particularly the subacetate of 
lead and the nitrateof mereury, occasions very abundant thick 
white sediments in it, entirely soluble in distilled yinegar*. 
7. The 
* Schwartz, an apothecary of Jena, having prepared a mixture with the 
nitrate of mercury and gum arabic, observed a precipitate which Juch 
ascribed to the gallic acid of the gum. Van Mons, who relates aoe 
thinks 
