754 Transactions of the American Institute. 



Mr. Nonnan Wiard remarked that cast iron will not oxydize but 

 a small way after having a slight coating of oxide, but wrought 

 iron will. 



Dr. D. D. Parmelee sjiid this coatinjj of oxide will in a short 

 time be no barrier to oxydation if in the open air. It is going on 

 every day in our water pipes. The oxide of manganese brought in 

 contact with iron will produce a second oxydation. 



Dr. L. Fcuchtwanger stated that manganese is much used to pro- 

 tect iron. The paint that is used for coloring, is merely to prevent 

 the air from attacking the iron. 



Mr. Norman Wiard said that the coating of English guns with 

 bronze was found very beneficial. He had seen some bronzed guns 

 in good condition after being on for twenty years. He had seen 

 it stated that brass and iron, in contact, produced a galvanic action 

 that prevented their use in guns. 



Mr. J. K. Fisher remarked that the fusing of brass and iron in 

 the casting stopped the galvanic action. This was known years ago. 



Prof. P. H. Vanderweyde stated that there are oxides that pro- 

 tect oxydation. The watch-spring made blue, is a thin film of 

 oxydation. A very thin film of the phosphuret of iron is what 

 protects Russia iron so long. 



Dr. L. Bradley related his experience in protecting sheet-iron 

 pipes from oxydation. British luster, asphaltum, varnish and other 

 articles failed to efiect that object, even when the iron was kept in 

 a very dry place. What he found to answer best was simple shel- 

 lac, mixed with lamp-black. 



Prof P. H. Vanderweyde said he found lamp-black varnish, made 

 from coal-tar, to be the best protection for iron pipes. 



Dr. John B. Rich tried melted paraffine on the inside of sheet- 

 iron pipes, and found it to answer very Avell. He coated his dental 

 instruments with it, by heating them and plunging them into 

 parafiine, and they afterwards were perfectly free from oxydation. 



Dr. D. D. Parmelee found plumbago, which resists the heat of 

 the blow-pipe, to be the best preventive of oxjdation. 



OXIDE OF ANTIMONY. 

 Dr. L. Fcuchtwanger exhibited a specimen of antimony ochre. 

 This mineral is now much used in glass-making. The Doctor exhi- 

 bited a beautiful porcelain lamp-shade, which contained the oxide 

 of antimony. He also exhibited a mineral found in great abun- 

 dance in Nova Scotia, and is used in maldng paint. It is simply 

 an oxide of iron. 



