oftlte Hya-hya Tree of Demerara. 33 



ether, is deposited by spontaneous evaporation in the form of a 

 white powder, which, as I have already remarked, differs httle 

 in chemical properties from the original juice. 



It has neither smell nor taste ; but it softens in the mouth, 

 and becomes very adhesive. Its density is about 955. When 

 heated in a tube, it softens into a thick fluid at 140°, retaining, 

 however, its whiteness and opacity. At 160° it becomes grey- 

 ish, more fluid, and translucent. At 212° it is greyish brown ; 

 and if it be kept some time at this temperature, and then redis- 

 solved in sulphuric ether, a black powder is separated, which 

 possesses the properties of charcoal. The temperature of boil- 

 ing water, therefore, evidently effects a slight decomposition. 

 When it has been heated to this degree, and then allowed to 

 eool, it is no longer brittle, but soft, ductile, and extremely vis- 

 cid. It recovers its brittleness and white powdery appearance, 

 however, on being redissolved in ether, and separated by spon- 

 taneous evaporation. 



Water does not act on the white powder in the cold. At 212° 

 the powder merely fuses into greyish globules, which rise to the 

 surface of the water, and form a stratum of a substance precisely 

 the same in nature with that procured by the same degree of 

 heat without the contact of water. 



Alcohol scarcely acts on it in the cold. In boiling alcohol, it 

 fuses into an opaque white mass, which, on cooling, concretes 

 into a white brittle solid, presenting a resinous fracture, and re- 

 taining its original properties. At the same time that it fuses, 

 however, the alcohol dissolves about a 250th of its weight, which 

 is recovered partly by refrigeration, and entirely by spontaneous 

 evaporation, without having undergone any sensible change. 



Sulphuric ether, at the temperature of 60° Fahr., dissolves 

 between a sixth and seventh of its weight, and rather more when 

 boiled on it. A colourless, transparent solution is thus pro- 

 cured, from which the powder separates unchanged, while the 

 ether is evaporated spontaneously. 



Oil of turpentine dissolves it in large quantity. I have not 

 examined the changes which then take place. 



A strong solution of caustic potass, even when boiled on it, 

 dissolves only a trace, which is thrown down unaltered on the 

 alkalki being neutralized. The portion not dissolved by the 



APUIL JUNE 1830. C 



