Intelligence and Miscellaneous Articles. 1 37 



In order to detect a chloride in a metallic bromide, it must be 

 mixed and powdered with bichromate of potash ; this mixture is to 

 be put into a small tubulated retort, to which a receiver containing 

 a sufficient quantity of solution of ammonia is adapted by a cork j 

 there is then poured upon the mixture an excess of fuming [con- 

 centrated ?j sulphuric acid, and the retort is to be heated. 



In employing only 0*012 of a gramme of chloride of sodium 

 mixed with 0*640 of a gramme of the bromide, indications of chro- 

 mic acid were obtained in the ammonia, but in this case it was not 

 by the colour that it was recognised ; it was detected by evapo- 

 rating the ammoniacal solution to dryness and exposing the residue 

 with a phosphate to the flame of the blow-pipe upon charcoal; 

 heated to redness. But if greater quantities of a mixture contain- 

 ing a smaller proportion of the chloride be employed, a yellowish 

 ammoniacal solution may be obtained ; this was done with a mixture 

 of 0053 gramme of the chloride with 0580 gr. of the bromide. M. 

 Rose endeavoured, but without success, to determine the quantity 

 of the chlorine by this process. If iodide of potassium be mixed 

 with excess of chromate of potash, and heated with sulphuric acid, 

 iodine only is disenjraged ; if a mixture of iodide of potassium with 

 chloride of potassium or sodium be treated in the same manner, no 

 chromate of chloride of chromium is obtained, but chlorine is first 

 evolved, and afterwards vapour of iodine, so that no chloride of 

 iodine is formed. It is only when the proportion of metallic chlo- 

 ride is greatly in excess, that chromate of chloride of chromium is 

 procured ; 12 parts of iodide of potassium with 60 parts of the chlo- 

 ride impart a slight yellow colour to the ammoniacal solution ; but 

 12 parts of iodide with 20 or .'^0 of chloride, did not yield a trace 

 of chromium to the ammoniacal solution. On account of this sin- 

 gular property ii is not possible to discover the presence of the 

 chloride in the iodide of potassium, by the same process as that by 

 which it is detected in the bromide. The best method of detecting 

 small quantities of metallic chloride in the iodide of potassium is 

 that proposed by M. Gay Lussac, founded upon the very slight so- 

 lubility of iodide of silver in ammonia. Add a solution of nitrate of 

 silver to a solution of the salt, until no further precipitation takes 

 place, then add ammonia in excess. If after agitation and filtering, 

 only opalescence occurs in the liquor on supersaturating it with 

 nitric acid, it is a proof that the iodide of potassium contains no 

 chloride or but a trace ; this last salt would be discovered by the 

 precipitation of chloride of silver when supersaturated by nitric acid. 

 — Journal de Pharmacies October 1837. 



ON THE EMPLOYMENT OF METALLIC SULPHURETS IN ANALYSTS. 

 BY MONS. E. F. ANTHON- 



It is well known that certain oxides possess the property of pre- 

 cipitating others from their solutions, by combining with the acid 

 of the dissolved oxide ; and this process has been adopted for the 

 separation of certain metallic oxides. 



Phil. Mag, S. 3. Vol. 12. No. 71. SuppL Jan. 1838. T 



