I am going into Hampshire on Sunday next to fish near Fordingbridge for a week, and to try the Avon and its tributary streams.
I was going to give you an account of some experiments which Mr. Faraday has made by my directions in generating gases in close vessels as liquids, but I find I have not time. I have already found an application of this discovery, which I hope will supersede steam, as a difference of a few degrees of temperature gives the elastic force of many atmospheres.
Hoping to see you soon, I am, with best respects to Mrs. Vivian, and love to the charming little Bessy,
My dear Sir, yours sincerely obliged,
H. Davy.
I proceed now to relate the history of an elaborate experimental enquiry, instituted for the purpose of ascertaining the chemical nature and causes of the well-known corrosive action of sea-water upon metallic copper; in order, if possible, to obviate that serious evil in naval economy—the rapid decay of the copper sheathing on the bottoms of our ships. An investigation which Sir Humphry Davy commenced in the year 1823, and prosecuted with his characteristic zeal and happy talent during a considerable period; when, at length, paradoxical as it may appear, the truth of his theory was completely established by the failure of his remedy!
From the several original documents which have been placed at my disposal, and from the valuable communications and kind assistance of my friend Mr. Knowles, I trust I shall be enabled to offer to the scientific reader a more complete and circumstantial history of this admirable enquiry than has been hitherto presented to the public.
The results he produced are equally interesting and important, whether we contemplate them biographically, as indicative of the peculiar genius by which they were obtained; or, scientifically, in their connexion with the electro-chemical theory, to the farther developement and illustration of which they have so powerfully contributed; or, economically, as the probable means by which the hand of Time may be averted, an increased durability imparted to rapidly perishable works of art, and monuments of human genius transmitted to posterity, in all their freshness, through a long succession of ages.
It is probable that, in the earliest period of naval architecture, some expedient[85] was practised, in order to protect ships' bottoms from the ravages of marine worms.[86] The use of metallic sheathing, however, is of ancient date. The galley supposed to have belonged to the Emperor Trajan was sheathed with sheets of lead, which were fastened with copper nails.[87] The same metal was also used in the earlier periods of our naval history;[88] and it is worthy of remark, that the circumstances which led to its disuse, were the rapid corrosion of the rother irons, (from the formation of a Voltaic circle,) and the accumulation of sea-weed.
In the year 1761, copper plates were first used as sheathing on the Alarm frigate, of thirty-two guns;[89] a second underwent this operation in 1765, a third in 1770, four in 1776, nine in 1777; and, in the course of the three following years, the whole British navy was coppered: an event which may be considered as forming an important era in the naval annals of the country.