1818.] Scientific Intelligence. 233 



water, but the weakest acid will bring back the colour ; it may 

 be reproduced even by blowing into the fluid through a tube. 

 As the colouring matter of red wines is supposed to reside 

 principally in the skin of the grape, the author prepared a 

 quantity of the skins, and reduced them to powder. In this 

 state he found that they were not soluble in ether, but that they 

 communicated to alcohol a deep red colour ; a paper stained 

 with this colour was rendered red by acids and green by alkalies. 

 M. Vogel informs us that he made a quantity of red wine from 

 black grapes for the purpose of his experiments, and that this 

 produced the greyish green precipitate with the acetate of lead ; 

 he also found the same coloured precipitate in two specimens of 

 red wine, the genuineness of which could not be suspected, 

 the one" from Chateau-Marguaux, and the other from the 

 neighbourhood of Coblentz. 



IX. On the Combinations of the Phosphnretted Hydrogenous 

 Compounds with the Hydi iodic Acid. By M. Houton Labil- 

 lardiere.* 



The author proposes to give an account of the combinations 

 of both the protophosphuretted hydrogen and the perphosphur- 

 etted hydrogen with hydriodic acid gas. By protophosphuretted 

 hydrogen, he informs us that he means the phcsphuretted 

 hydrogen which is disengaged by heat from phosphorous acid 

 formed by the action of the air; and by perphosphuretted hydro- 

 gen, that which is obtained from a mixture of phosphorus in 

 excess, lime, and water, the first portions only being collected 

 of what is disengaged by means of heat.f Protophosphuretted 

 hydrogen gas is distinguished from the perphosphuretted in its 

 not having the property of inflaming merely by the contact of 

 the air, and of not depositing phosphorus, both which circum- 

 stances occur in the perphosphuretted hydrogen. He observes, 

 however, that the protophosphuretted hydrogen will inflame in 

 atmospherical air, provided it be rarefied at ordinary temper- 

 atures, but at low temperatures a greater degree of rarefaction is 

 necessary. 



When protophosphuretted hydrogen and hydriodic acid are 

 mixed together over mercury with the proper precautions, we 

 obtain on the sides of the jar a layer of white cubical crystals, 

 which are decomposed by the contact of water, the protophos- 

 phuretted hydrogen being disengaged, and the hydriodic acid 

 being dissolved in the water. It is said that alcohol when freed 

 from water decomposes this compound, and it is also decom- 



* Abstracted from Journ. Pharm iii. 454. (Oct. 1817.) 



♦ The first of these substances lias been also named hvdrophosphoric gas, or 

 Dinydroguret of phosphorus, and appears to consist of one'atom of phosphorus to 

 two atoms or hydrogen; the second, which has been called simply phosphuretted 

 Hydro-en „ r hydroguret of phosphorus, appears to consist of oueatom of each of 

 jis ingredient*. 



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