EXAMINATION OP JALAP RESIN. 
25 
a combination of the resin with earths and metallic oxides 
in the solid form, an alcoholic solution of the resin was 
boiled with hydrate of lime and magnesia ; but none of the 
oxides could be detected in the filtered liquid. The resin 
was thrown down unaltered by water, nor was there in the 
residue any combination of the resin with the bases. Upon 
this an alcoholic solution was mixed with water till the re- 
sin began to separate ; it was then boiled with oxide of 
lead, hydrate of lime and magnesia, but no salt could be 
obtained in a solid state even in this manner. If a solution 
of the ammonia salt is boiled with hydrate of lime until no 
more ammonia is given off, a lime salt is formed, soluble in 
water and alcohol, but from which no resin can be sepa- 
rated by muriatic acid. Treated in the same manner with 
hydrate of barytes, a salt readily soluble in water and al- 
cohol is likewise obtained, but from which no resin could 
be separated by means of acids. Acetic acid dissolves the 
resin with ease ; concentrated nitric acid dissolves it in the 
cold unaltered; when ammonia is added it again separates; 
cold dilute nitric acid does not dissolve it ; on the application 
of heat it is dissolved with decomposition ; it is insoluble in 
cold dilute, but is decomposed by concentrated sulphuric 
acid ; moistened with it on a watch-glass, each particle be- 
comes, in about ten minutes, of a beautiful carmine red, 
and dissolves ; the liquid acquires a darker colour, and after 
some hours a brownish-black resinous body separates. 
Heated on platinum-foil, the resin first melts, and becomes 
brown, with evolution of a peculiar empyreumatic odour, 
and then burns with a bright, somewhat smokey flame, 
leaving behind a porous shining cinder, which at last dis- 
appears entirely. At 302° it melts to a bright yellow trans- 
parent mass, without however parting with any more water. 
The pure resin was pulverized, dried at 212°, and burnt 
with chromate of lead. It furnished — 
Equiv. Calculated. 
Carbon 
Hydrogen 
Oxygen 
56.49 
77.94 
35.5 
56.35 
7.89 
35.76 
42 56.66 
35 7.78 
20 35.56 
VOl. XI. — NO. I. 
3 
