The commercial bronze was slightly dezincified after 402 days of 

 exposure both in the sea water and in the bottom sediment at a depth of 

 2,500 feet. It was also reported to have dezincified at the surface in 

 the Pacific Ocean at Fort Amador, Panama Canal Zone, Reference 16. 



For all practical purposes the corrosion rates of commercial bronze 

 both in sea water and in the bottom sediments at the 6,000 foot and 

 2,500 foot depths can be considered constant with increasing time of 

 exposure. The corrosion rates at both depths were less than at the 

 surface and the rate at the 2,500 foot depth was slightly less than that 

 at the 6,000 foot depth. 



The corrosion rate of red brass, Figure 6, was the same in the 

 bottom sediments as in sea water at the 6,000 foot depth and decreased 

 with increasing time of exposure. However, at the 2,500 foot depth, 

 red brass corroded at a much slower rate in the bottom sediments than 

 in the sea water and the corrosion rates decreased as the duration of 

 exposure was increased. 



After about 400 days of exposure, red brass corroded at about the 

 same rate at the surface at Harbor Island, North Carolina in the 

 Atlantic Ocean, Reference 10, as it did at 2,500 feet in the Pacific 

 Ocean, At the surface in the Pacific Ocean it corroded at about the 

 same rate as at the 6,000 foot depth. 



Red brass was slightly dezincified, the first evidence of which 

 was found after 123 days of exposure in the bottom sediment at a depth 

 of 6,000 feet, Table 7, 



In general, red brass corroded less at the 2,500 foot depth than 

 at the 6,000 foot depth and the corrosion rates at both depths decreas- 

 ed as the time of exposure increased. 



Yellow brass, Figure 7, also corroded at the same rate in the 

 bottom sediments as in the sea water at the 6,000 foot depth and they 

 decreased asymptotically with time. At the 2,500 foot depth, yellow 

 brass corroded less in the bottom sediments than in the sea water and 

 the rates were nearly constant with increasing time of exposure. At a 

 depth of 4,250 feet in the Atlantic Ocean, Reference 13, the corrosion 

 rate of yellow brass increased with time of exposure and after 200 days 

 of exposure was the same as at a depth of 2,500 in the Pacific Ocean, 

 There was slight to moderate dezincif ication of yellow brass after 751 

 and 1064 days of exposure in the sea water at the 6,000 foot depth. 

 Table 7. After 181 days of exposure at the surface in the Pacific 

 Ocean, yellow brass corroded at a higher rate than at the 6,000 foot 

 depth and was slightly dezincified. 



Arsenical Admiralty, Figure 8, like yellow brass, corroded at the 

 same rate in the bottom sediments as in sea water at the 6,000 foot 

 depth and the rate decreased asymptotically with time. At the 2,500 

 foot depth it corroded at essentially the same rate in sea water as at 

 the 6,000 foot depth. In the bottom sediments at the 2,500 foot depth 

 arsenical admiralty corroded at a lower rate than in the sea water. 

 The corrosion rate of arsenical admiralty increased with time of ex- 

 posure at a depth of 4,250 feet in the Atlantic Ocean, Reference 13, and 



