92 Mr. Brande’s chemical Experiments 
by oxygen.* It likewise appears from that which has been 
stated, that the blue and green oxides (if they may be so 
called by way of distinction) are soluble in the mixture of 
nitric acid and alcohol, while the brown precipitate is 
insoluble. 
F. Alkalis do not form any precipitate when added to the 
solution of guaiacum in alcohol. 
3. Guaiacum is less soluble in sulphuric ether than in 
alcohol ; the properties of this solution nearly coincide with 
those just mentioned. 
4. Muriatic acid dissolves a small portion of guaiacum, the 
solution assuming a deep brown colour ; but if heat be ap- 
plied, the resin melts into a blackish mass, preventing any 
farther action from taking place. 
5. Sulphuric acid forms with guaiacum a deep red liquid, 
which, when fresh prepared, deposits a lilac coloured preci- 
pitate on the addition of water ; a precipitate is also formed 
* The following experiments appear to verify this supposition : 
Fifty grains of freshly pulverised guaiacum were introduced into a glass jar con- 
taining 60 cubic inches of oxy-muriatic acid gas. The resin speedily assumed a brown 
colour, having passed through several shades of green and blue. Liquid ammonia 
was poured on this brown substance, while yet immersed in the acid ; the whole 
became green ; it therefore seemed thus to be deprived of part of the oxygen which 
it apparently had acquired by the preceding experiment. An equal portion of the 
same guaiacum was exposed under similar circumstances to the action of oxy-muriatic 
acid, excepting that the glass in which the experiment was made, was covered with a 
black varnish, and placed in a dark apartment. On examining the result of this 
experiment, the resin was found to have undergone precisely the same changes as 
when exposed to light. Ammonia had also the same effect. 
Guaiacum was also exposed over mercury to oxygen gas ; the resin assumed after 
some days the green colour which a longer exposure to the atmosphere produces : 
this change was likewise found by a second experiment to be effected without the 
presence of light. 
