and particularly the Tartrates. 391 



oxidizement ; a conclusion which would have been more gene- 

 rally drawn, had a good form of protoxide preparation existed 

 in our Pharmacopoeias, or our shops. The precipitated sub- 

 carbonate of iron is merely the peroxide associated with only 

 from 3 to 5 per cent, of carbonic acid ; and is, therefore, not 

 entitled to its pharmaceutical name. 



A very pure, mild, and permanent form of a protoxide- 

 salt may, however, be easily obtained by exposing clean par- 

 ticles of iron, as bits of iron wire, to the action of tartaric 

 acid and | water at a gentle heat. An effervescence ensues, 

 hydrogen is disengaged from the water, the iron is oxidized to 

 a minimum, and is fixed in that state by its instantaneous 

 combination with the acid of tartar. This tartrate owes its 

 permanence to its insolubility ; but yet (like iron filings and 

 calomel) it acts energetically on the system. The proto- 

 tartrate of iron is nearly white, and pulverulent. The powdery 

 matter, as diffused in the liquid, may be decanted off the 

 iron into a filter, and washed with a little water. It has a 

 mild chalybeate taste, and will constitute a valuable accession 

 to the Materia Medica. 



At a dull red heat, this tartrate readily takes fire, and 

 burns slowly away like tinder, after its removal from the 

 source of heat, with the exhalation of a caromel odour; while 

 the oxide of iron becomes peroxidized. 



Glasgow, December 5, 1829. 



