218 Miseellaneous Intelligence, 



acted upon by boiling alcohol : the latter will dissolve the acid ma- 

 late of altheine, oil, &c. : the different alcoholic decoctions are to be 

 put together and will throw down a crystalline deposite as they cool ; 

 the latter is to be separated and dissolved in water, and the solution, 

 when filtered, is to be evaporated by a moderate heat, until like a 

 syrup, and then set aside to crystallize. The crystals procured are 

 to be washed with a small quantity of pure water, to separate the 

 yellow matter from them, and then dried upon paper. These crys- 

 tals appear, to the naked eye, like grains, needles, and feathers, but 

 under the microscope present a hexaedral form. They are of a fine 

 emerald green colour, transparent, brilliant, inodorous; unaltered 

 in the air ; they redden litmus paper, are soluble in water, and 

 insoluble in alcohol. The aqueous solution of these crystals, acted 

 upon by cold magnesia and filtered, then restores the colour of 

 reddened litmus paper ; renders syrup of violets green ; and when 

 evaporated furnishes the altheine free from malic acid. When thus 

 pure, the substance crystallizes in regular hexaedral forms or in 

 rhomboidal octoedrons ; it affects litmus and violets as just described: 

 it is transparent, of an emerald green colour, brilliant, inodorous, 

 slightly sapid, unaltered by air, very soluble in water, not soluble in 

 alcohol, soluble in acetic acid, with which it forms a crystalline 

 salt. — Ann. de Chimicy xxxiv. 201. 



35. Rheine, a new Substance from Rhubarb. — By acting upon 

 one part of Chinese rhubarb with 8 parts of nitric acid, s. g. 1.32, 

 at a moderate temperature, reducing the whole to the consistence 

 of syrup, and then diffusing it through water, M. Vaudin obtained 

 a precipitate which possessed peculiar characters, and to which he 

 gave the name of Rheine. When dry, it is of an orange yellow 

 colour, without any particular odour, and slightly bitter. It dis- 

 solves in water as well as in alcohol and ether : the solutions be- 

 come yellow by acids, and rose red by alkalis. It burns nearly in 

 the manner of amadou. Rhubarb acted upon by ether only gave 

 a similar substance, a circumstance which proves that Rheine exists 

 ready formed in rhubarb, and that it is not acted upon by nitric 

 acid. — Anji. de Chimie, xxxiv, 192. 



36. On Dragon's Blood, and a new Substance which it contains^ 

 by M. Melandri. — Pure dragon's blood is, according to M. Me- 

 landri, a scarce substance ; the drops in which it occurs are rarely 

 transparent, generally opaque, and with a rough fracture : its colour 

 is blood red. Besides being soluble in alcohol it is entirely soluble 

 in oil and also in hot water, though a large quantity of the latter 

 fluid is required for the purpose. The aqueous solution is bitter, 

 astringent, and of a fine purple colour ; by cooling, it becomes milky 

 and red. Gelatine does not alter its appearance ; a proof that the sub- 

 stance contains no tannin. Sulphate of iron forms a pale reddish 

 precipitate, so that no evidence of gallic acid is afforded. 



