t 388 ] 



to (land long in copper veflels, contrafts a coppery 

 tafte, and unwholefome quality. 



It is very remarkable, that water becomes more 

 ftrongly impregnated with the metal on {landing in 

 the cold, than if boiled in the vefTel for a much 

 longer fpace. ' The fame is faid to take place in re- 

 gard to vegetable acids. Hence the confedlioners 

 venture to prepare the acid fyrups even of orange 

 and lemon juice in copper veflels. Thefe acid pre- 

 parations, according to Dr. Lewis, acquire no ill 

 tafte from the metal while kept in a boiling heat, 

 whereas if kept cold in fuch veflels, they foon be- 

 come impregnated with the difagreeable tafte and 

 pernicious qualities of the copper. But the mere 

 tafte is by no means a fatisfadory teft, becaufe a 

 very flight impregnation of copper may be fo far 

 difguifed by the acid and fugar as to elude the tafte, 

 and yet prove injurious to the nervous fyftem. 

 Mineral acids are acknowledged to ad more power- 

 fully on this metal when aided by heatj and ad- 

 mitting that the adion of vegetable acids is on the 

 contrary weakened by heat, yet we have no proof 

 that it is thereby wholly deftroyed. 



Preparations of Copper ufed in Medicine. 



This metal with the vitriolick acid yields vitri- 

 olate copper, or blue vitriol i — with the vegetabl« 



acid. 



