Intelligence and Miscellaneous Articles. 607 



For peroxide of iron. — Tincture of galls indicated the presence of 

 l-300,000dth of peroxide of iron in a solution of sulphate of per- 

 oxide of iron by i-endering it of a slight violet colour. 



A solution of ferroprussiate of potash indicated the presence of 

 l-420,000dth of the same salt. 



For copper. — A solution of ammonia gave after several hours a 

 slight blue colour to a solution of sulphate of copper containing 

 l-9400dth of oxide of copper. 



A solution of prussiate of potash rendered the presence of 

 l-78,000dth of the same salt visible. 



Polished iron showed the presence of 1-125 .OOOdth of oxide of 

 copper, or 1-1 56, OOOdth of metallic copper, if the solution was 

 acidulated by a drop of nitric acid. 



For lead. — A piece of zinc precipitated lead from a solution of the 

 nitrate when l-3000dth of oxide was present. 



An excess of sulphuric acid occasioned a precipitate in a solution 

 of the same salt containing 1-20, OOOdth oxide. 



A solution of chromate of potash occasioned a cloudiness in a so- 

 lution containing 1-70, OOOdth of the same oxide. 



A solution of hydrosulphuric acid blackened a solution containing 

 l-350,000dth. 



For silver. — Chromate of lead produced a slight red precipitate in 

 a solution of nitrg,te of silver containing l-10,000dth of oxide. 

 No reaction took place in a solution containing above l-20,000dth. 



Arsenite of potash produced a decided yellow precipitate with 

 l-6000dth oxide in solution, but none with l-20,000dth. 



Iodide of potassium indicated the presence of l-4000dth oxide, 

 but produced no action with 1-30, OOOdth. 



A solution of hydrosulphuric acid precipitated a solution contain- 

 ing l-35,000dth of oxide. 



Chloride of sodium produces a cloudiness in a solution which con- 

 tained only 1-240, OOOdth. — Extracted by E. F. Teschemacher from 

 the Journal fur Praktische Chemie, No. 1, 1841. 



The following are the additional particulars relative to anilin, re- 

 ferred to in p. 281. 



Anilin is a base which with acids readily yields fine crystallized 

 salts. "When exposed to atmospheric air, it soon becomes yellow and 

 eventually brown, and the same resinous body is formed which is 

 separated from it by distillation. It must therefore be preserved 

 out of the contact of air, and to prevent its action should be quickly 

 distilled. Anilin may contain a little water, from which it is freed 

 by distillation, taking care, when a third of it has been distilled, to 

 change the receiver ; by this method only it is obtained perfectly 

 anhydrous. Boiling anilin dissolves sulphur and iodine in large 

 quantity, and deposits them on cooling, in crystals. Nitric acid, 

 under certain circumstances, converts anilin into a blue or green 

 body, which docs not appear to be indigo ; this substance has, how- 

 ever, been hitherto obtained only uncertainly and in small quantity, 

 as it undergoes fresh decomposition by the nitric acid. Chromic 



