Sir Humphry Davy suggests a chemical method for unrolling the ancient Papyri.--He is encouraged by the Government to proceed to Naples for that purpose.--He embarks at Dover.--His experiments on the Rhine, the Danube, the Raab, the Save, the Ironzo, the Po, and the Tiber, in order to explain the formation of mists on rivers and lakes.--His arrival and reception at Naples.--He visits the excavations at Herculaneum.--He concludes that it was overwhelmed by sand and ashes, but had never been exposed to burning matter.--He commences his attempt of unrolling the Papyri.--His failure.--He complains of the persons at the head of the department in the Museum.--He analyses the waters of the Baths of Lucca.--His return to England.--Death of Sir Joseph Banks.--He is elected President of the Royal Society.--Some remarks on that event.--He visits Penzance.--Is honoured by a public dinner.--Electro-magnetic discoveries of Oersted extended by Davy.--He examines Electrical Phenomena in vacuo.--The results of his experiments questioned.--He enquires into the state of the water, and aëriform matter in the cavities of crystals.--The interesting results of his enquiry confirm the views of the Plutonists 160 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