392- 



r.XPEillMF.NTS OX GUAlAtUM. 



stated, tlint the blue and green oxides (if they may be so called 



by way of distinction) are soluble in the mixtureof nitric acid 



and alcohol, while the brown precipitate is insoluble. 



Alkalis do not F. Alkalis do not form any precipitate when added to the 



precipiratethe solution of iruaiacum in alcohol. 



alcoholic solu- *= 



tion. 3. Guaiacutn is less soluble in sulphuric ether than in al- 



ethe ^and^onrl ^^^^^^ > ^^^^ properties of this solution nearly coincide m ith 



acids upon those just mentioned, 

 uaiacum. ^^ Muriatic acid dissolves a small portion of g'uaiacum, the 



solution assuming a deep brown colour ; but if heat be applied, 

 the resin melts into a blackish maiss, 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 precipi- 

 tate on the addition of water ; a precipitate is also formed by 

 the alkalis. If heat be employed in forming this solution, the 

 resin is speedily decomposed ; and if the whoje of the acid be 

 evaporated, there remains a black coaly substance, together 

 with some sulphate of lime. 



Action of nitric 6. Nitric acid appears to exert a more powerful action on 



^'^l ."Z*^ guaiacum than on any of the resinous bodies. 



, guaiacum. & J 



100 grains of pure guaiacum previously reduced to powder, 

 were cautiously added to two ounces of nitric acid, of the spe- 

 cific gravity of 1.39. The resin at first assumed a dark green 

 colour, a violent eflcrvescencc was produced, atterided with the 

 emission of miicli. nitrous gas, and the whole was dissolved 



became green ; it therefore seemed thus to be deprived of part of 

 the oxygen which it apparently had acquired by the preceding ex- 

 periment. An equal portion of the same guaiacum was exposed 

 under similar circumstances to the action of oxy-muriatic acid^ 

 excepting that the glass iu 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 ta 

 light; Ammonia had also tlie same effect. 



Guaiacum was also exposed over mercury to oxygen gas; the 

 resin a,^sumed after some days the green colour which a longer 

 wtposure to the atmosphere produces : this change was likewise 

 found by a second experiment to be effected without the presence 

 of li-lit" 



with" 



