388 



MISCELLANEOUS. 



Method of distinguishing Iron from Steel. 



Drop a little weak aqua-fortis on the metal ; let it 

 remain for a few minutes, and then wash it off with 

 water. If it is steel, the spot will be black, but if 

 iron, the spot will be whitish grey. 



A Test for discovering the presence of Lead ^ 

 Copper, 8^c, in Wines. 



Lead and copper being sometimes used to 

 amend the taste of wines, and these metals being 

 of a very poisonous quality, a test that shall detect 

 this is of great value. The following test is the 

 discovery of Mr. Hanhemann. 



Equal parts of oyster shells and crude sulphur 

 are to be kept in a white heat for a quarter of an 

 hour, and, when cold, this is to be mixed with 

 an equal quantity of acidulous tartrite of potash, 

 and put into a strong bottle with common water 

 for an hour, and then decanted into bottles holding 

 an ounce each, with twenty drops of muriatic acid 

 in each. 



This liquor precipitates the least quantities of 

 lead, copper, &c. from wines, in a very sensible 

 black precipitate. 



To make Pearl White. 



Put some good aqua-fortis into a Florence flask, 

 and gradually add to it bismuth broken into small 

 pieces, till no more dissolves ; tlien let the solution 

 remain till it is transparent. Add to this some 



