MISCELLANEOUS. 



rise, so as to cover the sides, forming a multitude 

 of ramifications heaped one upon the other, which 

 will sometimes pass over the edge of the vessel, 

 and extend themselves on the outside with all 

 the appearance of a plant. 



To change Iron apparently into Copper. 



Dissolve some blue vitriol (sulphate of copper) 

 in water, and dip into the solution a piece of 

 bright iron or steel ; in a few seconds it may be 

 taken out, when it will be apparently turned to 

 copper. This is a deception ; the iron is not 

 changed into copper ; it is only encrusted over 

 with that metal, as may be easily seen by removing 

 the copper by a file. The iron having a stronger 

 attraction for sulphuric acid than copper, it takes 

 the acid from the latter, which is consequently 

 precipitated. This process is used for obtaining 

 the copper from waters near mines that contain a 

 great quantity of that metal. Iron plates are put 

 into them, which become incrusted with copper, 

 which is scraped off. 



To prepare the Precipitate ofCassius* 



This beautiful purple colour is extremely useful 

 to enamellers and glass stainers. To make it, pro- 

 ceed as follows. 



Dissolve some gold in aqua regia (nitro-muriatic 

 acid), and also dissolve some pure tin in diluted 

 aqua regia, and pour it into the solution of gold. 

 A purple powder will be precipitated, which must 

 be collected and washed in distilled water. 



