ON THE GAMBOGE TREE OF SIAM. 
43 
A series of experiments were made, in the summer of 1840, on 
the use of metallic and other solutions for the preservation of wood. 
A deep saw-cut was made all round the circumference of some 
growing trees near their base, into which the solutions were intro- 
duced by forming a basin of clay beneath the cut ; thus the solution 
took the place of the ascending sap, and in periods of time varying 
from one to three days was found to have impregnated even the 
topmost leaves of trees fifty feet high. The trees were chiefly beech 
and larch. After impregnation they were felled, and specimens 
about five feet long by two inches square were cut out, and packed 
in decaying sawdust in a warm damp cellar, where they were left 
for seven years. The details of the experiment are given in a table, 
by which the following general rules are made to appear: — The 
pieces of wood saturated with sulphate of copper in the proportion 
of one pound to one gallon of water, or with acetate of copper in 
the proportion of one pound to one pint of vinegar and one gallon 
of water, were found in perfect preservation, clean, dry and free 
from fungus ; but the remaining pieces, which were saturated with 
nitrate of soda, prussiate of potash, acetate of iron, sulphate of 
iron, common salt and kreosote, presented much decay and a large 
growth of fungi. 
The results obtained from solutions of corrosive sublimate, one- 
eighteenth of a pound to a gallon of water (Kyan's proportion), 
varied in an anomalous manner. 
The paper was accompanied by specimens of the wood, showing 
how complete had been the saturation.— Chemical Gazette, July 
1, 1850. 
ON THE GAMBOGE TREE OF SIAM. 
By Dr. Christison, V. P., F. R. S. E. 
Although gamboge has been known in European commerce for 
nearly two centuries and a half, and its applications in the arts have 
been extended in recent times, the tree which produces it is still 
unknown to botanists. 
The late Dr. Graham, in 1836, was the first to describe accurately 
a species of Garcinia, which inhabits Ceylon, and which is well 
