350 Comparative Analysis of the Gum Resins. 
hol, which inclined me to think that the lime contained in 
the gum-myrrh is saturated with acetic acid, perhaps also 
with carbonic acid; for, if we pour into the solution of this 
gum sulphuric acid, a slight effervescence is manifested, and 
a precipitate of sulphate of lime. 
From the above it appears that gum-myrrh is not entirely 
separated from its solvent by the nitrate of lead; since of 
the 23 grammes, only 16 were precipitated with the oxide 
of lead, which could only be owing to the nitric acid set at 
liberty: fora salt of lead surcharged with oxide, such as 
ithe subacetate of lead, precipitates almost entirely the solu- 
tion of gum-myrrh; and totally, if we add a little alkali. to 
the mixture. 
D. What remained on the filter.B, when well dried and 
weighed, was heated with alcohol, which dissolved all the 
resinous parts, and Ifet a soft transparent matter insoluble 
in boiling water and weighing sixgrammes after desicca- 
tion. It had all the properties of the gummy matter which 
I have already described. i ror i 
E. The alcoholic solution D, when mixed with spirit of 
wine which hacdbeén used in washing the filter, gave upon 
evaporation 11°5 grammes of a brown resin of a bitter aro- 
matic taste, similar to that of myrrh. 
1. This resin easily softens between the fingers, melts at 
48° of Reaumur, and does not become idio-electrical. 
2. It gives out an aromatic smoke when burning, and 
yields upon distillation the same product as the resins. 
3. With potash it produces a soap, the solution of which 
in water passes turbid through the filter. 
4, Thirty-three grammes of nitric acid at 38° poured upon 
5°5 grammes of myrrh-resin made it take a blackish colour: 
this mixture when distilled emitted some scanty red vapours. 
After having obtained a product of about 20 grammes of 
this solution, the retort was removed from the fire: it con- 
tained a supernatant resiniformed substance of an orange- 
colour, which when washed and dried was of a pale yel- 
low ; it weighed a. gramme and avhalf: it was pulverulent, 
bitter, not very ftisible, partly soluble in water, furnishing 
on its’ union with potash a soapy compound, which is very 
easily dissolved in water, to which it communicates a red 
colour without affecting its transparency. This resini- 
forined substance contains plenty of charcoal, and is not 
sensibly altered on heating it with nitric acid, which merely 
dissolves it. It acts in other respects precisely like that of 
other resins when treated by the nitric acid. 
The nitrie liquor (2boye which this substance dgaed) 
when 
