“I have lately made a discovery of which you will for many reasons be glad. I have found a complete method of preserving the copper sheeting of ships, which now readily corrodes. It is by rendering it negatively electrical. My results are of the most beautiful and unequivocal kind: a mass of tin renders a surface of copper 200 or 300 times its own size sufficiently electrical to have no action on sea water. “I was led to this discovery by principle, as you will easily imagine; and the saving to government and the country by it will be immense. I am going to apply it immediately to the navy. I might have made an immense fortune by a patent for this discovery, but I have given it to my country; for in everything connected with interest, I am resolved to live and die at least ‘_sans tâche_.’” His method of rendering the copper negatively electric consisted in affixing to the sheets a number of short bars of iron or zinc, properly curved to the shape of the vessel. In this way the “protectors,” as the zinc or iron bars were called, gradually corroded, whilst the copper remained unattacked. But, as Dr. Paris remarks, the truth of the theory was completely established by the failure of the remedy. The ship’s bottom became so foul by the adhesion of shells and weed that her speed was greatly impeded, and after a number of trials, in the course of which a steam vessel was placed at his disposal, in which he made a voyage to Norway and back, the Admiralty directed the protectors to be removed. To add to his mortification, the order was issued immediately after a communication to the Royal Society announcing the complete success of his plan. Throughout the whole of this business he was exposed to a number of vexatious attacks, which greatly embittered him and reacted disastrously upon his health and character. So long as there was the hope of success and the prospect of reward his claims to the originality of the invention were contested: no sooner was the project abandoned than he was assailed in the periodical press and made an object of sarcasm and censure. As might be imagined, his philosophy was not proof against such attacks. He wrote to his friend Children-- “A mind of much sensibility might be disgusted, and one might be induced to say why should I labour for public objects, merely to meet abuse?--I am irritated by them more than I ought to be; but I am getting wiser every day--recollecting Galileo, and the times when philosophers and public benefactors were burnt for their services.”