332 Intelligence and Miscellaneous Articles. 



coals, was unquestionably determined to be metallic arsenic. Some 

 other portions of phosphoric acid, procured from other druggists at 

 Berlin, gave the same results. M. Barwald satisfied himself that 

 neither the vessel used, the nitric acid nor the sulphuretted hydrogen 

 contained any arsenic, and that this metnl came from the phospho- 

 rus. He learnt from another druggist that water in which phosphorus 

 was long kept also contained arsenic. This fact was confirmed by 

 Wittstock j but phosphorus which he himself prepared did not con- 

 tain any arsenic. His experiments also showed that a considerable 

 quantity of arsenic might be mixed wiih phosphorus without materially 

 altering its appearance j but, according to the proportion of the ar- 

 senic, its colour was deeper and of a more marked yellow gray, espe- 

 cially at the surface: if the quantity of arsenic was very considerable, 

 its colour was steel gray, but it was soft and ductile like wax. 

 M. Barwald attributed the presence of this metal in the phosphorus 

 to the sulphuric acid employed to'prepare it. M. Liebig also sa- 

 tisfied himself that the phosphorus bought of the druggists of 

 Frankfort contained rather a large quantity of arsenic. He found, as 

 the chemists already mentioned had done, that during the oxidation 

 of the phosphorus by the diluted nitric acid, phosphorous acid is prin- 

 cipally formed ; and he also observed that when this acid solution was 

 evaporated to expel the nitric acid, there was developed phosphuretted 

 hydrogen when it had arrived at a certain degree of concentration, 

 and this reduced the arsenic or arsenious acid which it contained, and 

 a black heavy powder was deposited, which was metallic arsenic. 

 M. Liebig proposes, in order to purify phosphoric acid, to substitute 

 phosphorous acid for sulphuretted hydrogen, this latter requiring se- 

 veral days for its action. The process which he proposes is the fol- 

 lowing : oxidize two parts of phosphorus by dilute nitric acid, and 

 evaporate the liquor until the arsenic is deposited j at the same time 

 there is to be placed in a funnel, deposited in a cellar, one part of 

 phosphorus in a glass tube ; the phosphatic acid which is obtained is 

 to be used to purify the phosphoric acid a second time when diluted 

 with water : the mixed liquors are to be evaporated, and if arsenic is 

 again deposited, the operation is to be repeated until no effect is pro- 

 duced by the addition of phosphatic acid. 



The above is extracted from the Annalen der Pharm. 1834. The 

 editor of the Journal de Chimie Me'dicale adds, that some experiments 

 which he had made showed that some phosphoric acid which was 

 prepared fifteen years since contained arsenic, but they had not found 

 it in any other specimen, nor in the water in which phosphorus had 

 been kept for four years. — Journal de Chimie Me'dicale, April 1835. 



COMPOSITION OF OXYCHLORIDE OF ANTIMONY. BY J. F. W. 

 JOHNSTON, F.R.S.E., &C, PROF. CHEM. IN THE UNIV. DURHAM. 



Professor Johnston remarks that " we have many analyses of this 

 substance, no two of which agree, obviously because having washed 

 it more or less, each chemist operated upon a mixture in which the 

 relative quantities of oxide and chloride of antimony actually differed. 



