Method of Proving Hint; $i 



winch appears to me probable, it would mil be one of the 

 oldeft of its kind in Italy, and belong to the oil-paintings of 

 the fourteenth century, fame of which are mentioned by 

 Dominici and Tirabofchi prior to the difcovery of the cele- 

 brated Van Eye. 



(To be concluded in the next Number.) 



VII. Method of dlj covering iVbelherJVine has been adulterated 

 ■zvith any Metals prejudicial to the Health. By M. HAHNE- 

 MANN. From Bibliothequc Phyfico-6conomique. 



1 HE property which liver of fulphur (alkaline fulphures) 

 And hepatic air (fulphurated hydrogen) poffefs of precipita- 

 ting lead in a black form, has been long ago made public^ 

 and this property has been employed to determine the qua- 

 lity of wines by means of the liquor probatorius IVirtem- 

 hergenjis, or Wirtemberg proving liquor. 



But, in trying wines fuppofed to have been adulterated, this 

 proof does move hurt than fervice, becaufe it precipitates iron 

 of the fame colour as the pernicious lead. Many wine-mer- 

 chants therefore of the greateft rcfpc£tability, rendered by 

 thefe means fufpe&ed, have been ruined. 



There was wanting then a rc-agent, which mould difcover 

 in wine thole metals only which are prejudicial to the health 

 of man. 



The following liquor precipitates lead and copper in a. 

 black form, and arfenic of an orange colour, &c. but does, 

 not precipitate iron. The laft, which is not noxious, and 

 rather falutary to the conftitution, frequently gets into wine* 

 by accident. 



Method of preparing the Proving Liquor, 



iVlix equal parts of oyfter fliells and crude fulphur in a 

 fine powder, arid- put the mixture into a crucible. Heat it 



in 



