[79] An explanation which the experiments of Mr. Faraday, on the condensation of the gases, to be immediately described, will most fully justify. CHAPTER XIII. The Liquefaction of Chlorine Gas first effected by Mr. Faraday, and witnessed by the Author.--Sir H. Davy continues the investigation.--His paper on the application of Liquefiable Gases as mechanical agents.--Other probable uses of these bodies.--He proposes several methods to prevent the fumes which arise from Smelting-furnaces.--Importance of the subject. His Letters to Mr. Vivian.--The Government solicit the advice of the Royal Society on the subject of protecting the Copper Sheathing of Ships from the action of sea-water.--Sir H. Davy charges himself with this enquiry.--He proposes a plan of protection founded on Voltaic principles.--His numerous experiments.--He embarks on board the Comet steam-vessel bound to Heligoland, in order to try his plan on a vessel in motion.--He arrives at Mandal, lands, and fishes in the lakes.--The Protectors washed away.--He teaches the inhabitants of Christiansand to crimp fish--He remains a few days at Arendal.--A Norwegian dinner.--The Protectors are examined and weighed.--Results of the experiment.--The steam-vessel proceeds up the Glommen.--He visits the great waterfall--Passes into Sweden.--Has an interview with the Crown Prince of Denmark, and afterwards with Prince Christian at Copenhagen.--He visits Professor Oersted.--He proceeds to Bremen to see Dr. Olbers.--Returns to England.--His third paper read before the Royal Society.--Voltaic influence of patches of rust.--A small quantity of fluid sufficient to complete the circuit.--He receives from the Royal Society the Royal Medal.--The Progress of Voltaic discovery reviewed.--The principle is of extensive application.--The Author's researches into the cause of the solution of Lead in spring water.--An account of the numerous trials of Protectors.--Failure of the plan.--Report of the French on the state of the protected frigate La Constance.--Dr. Revere's new plan of Protection. Every incident, however trifling, if it relates to a great scientific discovery, merits the attention of the historian. As it accidentally occurred to me, and to me alone, to witness the original experiment by which Mr. Faraday first condensed chlorine gas into a liquid, I shall here state the circumstances under which its liquefaction was effected.