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VI. On the corrosion of copper sheeting by sea water, and on 
methods of preventing this effect ; and on their application to 
ships of war and other ships. By Sir Humphry Davy, Bart. 
Pres. R. S. 
Read January 22, 1824. 
1. The rapid decay of the copper sheeting of His Majesty’s 
ships of war, and the uncertainty of the time of its duration, 
have long attracted the attention of those persons most con- 
cerned in the naval interests of the country. Having had 
my enquiries directed to this important object by the Com- 
missioners of the Navy Board, and a Committee of the Royal 
Society having been appointed to consider of it, I entered into 
an experimental investigation of the causes of the action of 
sea water upon copper. In pursuing this investigation, I 
have ascertained many facts which I think not unworthy of 
the notice of the Royal Society, as they promise to illustrate 
some obscure parts of electro-chemical science ; and likewise 
seem to offer important practical applications. 
2. It has been generally supposed that sea water had little 
or no action on pure copper, and that the rapid decay of the 
copper on certain ships was owing to its impurity. On trying, 
however, the action of sea water upon two specimens of cop- 
per, sent by John Vivian, Esq. to Mr. Faraday for analysis, 
I found the specimen which appeared absolutely pure, was 
acted upon even more rapidly than the specimen which con- 
tained alloy : and, on pursuing the enquiry with specimens 
of various kinds of copper which had been collected by the 
