i879-] 
Proceedings of Societies. 
325 
nitric acid nitrous fumes are given out, and the mass gradually 
becomes yellow, and finally a beautiful orange-coloured mass 
was obtained. The mass was to a great extent soluble in abso- 
lute alcohol, leaving behind a small quantity of a yellowish body. 
A quantity of alcoholic extract was precipitated with acetate of 
lead, the precipitate was thoroughly washed with absolute alcohol, 
aad then decomposed by means of dilute sulphuric acid. The 
mass was dissolved again in absolute alcohol, then separated from 
sulphate of lead.. This separated alcoholic extract was again 
precipitated by sugar of lead, and, after filtering and washing, 
the precipitate was dried partially in an air-bath, and carried 
under the receiver of an air-pump and dried over sulphuric acid. 
This lead salt exploded when heated. The amount of lead was 
estimated as oxide by igniting it with nitric acid, and the salt was 
subjected to organic combustion. Nitrogen was determined by 
Dumas’s method. The following numbers were obtained as the 
mean results : — 
Carbon ... 
26-93 
Hydrogen 
4*n 
N0 2 
18-44 
PbO 
47*42 
Oxygen . . . 
3* 10 
ioo-oo 
The author then took alcoholic extract of the original lacquer 
and precipitated it with acetate of lead. After requisite purifica- 
tion and drying the precipitate, it was analysed, the lead being 
determined as before. The following is the mean of two experi- 
ments which were tried : — 
Carbon ... 
Hydrogen 
PbO 
Oxygen ... 
... 50-450 
••• 5705 
••• 3775 
... 40-070 
100-000 
The gum is soluble in cold as well as in warm water. It has no 
smell, almost no taste ; it has a yellowish, or rather brownish, 
colour, and is of a non-crystalline body. It is quite insoluble in 
alcohol. On subjecting this substance to organic analysis the 
following percentage of hydrogen, carbon, and oxygen was 
obtained : — 
Carbon ... 
41*20 
41*45 
Hydrogen 
6 * 5 i 
6-58 
Oxygen ... 
52*29 
51*97 
100-00 
100-00 
These analyses yield a formula approximating to the composition 
of common gum. The residue is, the author thinks, nothing 
more than the mixture of cellulose, bark, dust, &c. 
