in the Waters of the Ocean. 9 



and sent her to the coast of Africa. Not many months 

 after she returned to this country with the copper in the same 

 state as that of the Bonetta. The merchants said — the copper- 

 smelters were inexperienced hands — they did not know their 

 business — the sheathing was improperly made; and they 

 brought an action against the Company, who defended it. 



Upon the trial some of the most eminent scientific men of 

 the day gave evidence that there was nothing in sea water 

 which could produce such rapid decay of the copper, and the 

 jury, in consequence, brought in a verdict for the plaintiffs. 



Now contrast this with what has happened to me within the 

 last two months. An eminent copper manufacturer of South 

 Wales, who had heard nothing of the investigations in which 

 I had been engaged, came to me with two samples of copper 

 which he wished me to analyze. The one was of new metal, 

 and the other part of the sheathing of a ship which had just 

 returned from Africa, after a voyage of a few months, the 

 copper being in a state of utter decay. He stated that the 

 merchants to whom the vessel belonged had brought an action 

 against him on the plea that the copper was imperfect, and he 

 wished for my evidence upon the subject, as he well knew that 

 the copper was perfectly good. Instead of entering upon the 

 analysis I gave him a copy of my report upon the waters of 

 the western coast of Africa, which he sent to the merchants, 

 and nothing further has been heard of the action. 



But it may perhaps be said that little good will arise from 

 pointing out the evil, unless we are prepared to propose some 

 remedy for it ; not that I agree to this, for the existence of the 

 sulphuretted hydrogen is so readily tested, even by the rough- 

 est hands, that nothing can be easier than to ascertain and 

 avoid the localities in which it prevails; motives for which 

 course I shall presently mention, of greater weight even than 

 the preservation of the copper. 



But I think that the remedy is certainly within our com- 

 mand. The principle of protection proposed by Sir H. Davy 

 is quite applicable to it, with some additional precautions sug- 

 gested by this newly-discovered destructive agent, which had 

 escaped his notice. 



It is well known that his experiments were conducted chiefly 

 with zinc and iron, as the active elements of protection ; and 

 he was led ultimately to the adoption of cast iron, " as the 

 substance which is cheapest, most easily procured, and like- 

 wise most fitted for the protection of the copper*." 



But this is not the case with regard to sulphuretted hydro- 



* Phil. Trans., June 1824, p. 243 ; [or Phil. Mac. First Series, vol. lxv., 

 p. 204.] 



