Experiments on Staining Wood * 13i 
2. By Means of Spirit of Wine . 
Experiment I.- — When dragon's blood and gamboge 
were merely dissolved in spirit of wine, the extract was 
not sufficiently strong, and the dye was of no use. The 
process, however, succeeds when the spirit of wine has 
been long boiled over a slow lire, till it is almost evapo- 
rated. The piece of wood appears then of a dark red co- 
lour, which is improved if the wood be washed in pure 
spirit of wine. But the colour is never so bright as that 
produced by means of an oil. 
II. Gamboge with spirit of wine gave to wood in this 
manner a yellow, and gamboge and dragon’s blood a yel- 
lowish red, colour. 
3. Experiment with Wax. 
White wood boiled in spirit of wine, to which, when it 
began to boil, wax was added, could not be made to as- 
sume the green or the red dye, even in its small cross 
veins, which were exceedingly porous. 
4. Experiments with dissolved Salts and Metals . 
The following experiments with these substances, 
which have already been described by Macquer, seemed* 
to be most successful. 
Experiment I. — A solution of common alum (sulphate 
of alumine) penetrates exceedingly well into wood which 
has been digested in it; so that hopes may be enter- 
tained of something being effected by it, as the white 
colour of every kind of wood becomes whiter by so- 
lutions of saline substances : this may be of great use to 
artists. 
II. Wood soaked in a solution of gold assumed a 
red colour, but the inner part was only of a yellowish 
red. 
