162 Biographical Account of 



The Bakerian lecture for 1826, ** On the relation of 

 electrical and chemical changes." 



These were important papers, having for their object the 

 application of zinc protectors to the copper sheathing 

 of ships, so as to prevent the latter from being corroded 

 by the action of sea water. As the plan proposed appeared 

 fraught with so many important consequences to ship 

 owners, it was immediately applied to practice. Several 

 vessels were sent on long voyages under the protecting 

 influence of minute portions of zinc, equal together to ^J-^ 

 or y^j^ of the surface of the copper. The copper was found 

 to be completely protected — not a particle of it had corroded 

 — but, in some instances, the accumulation of sea weeds 

 and shell fish in consequence of the surface of the copper 

 being covered with a coating of zinc (for such is the conse- 

 quence of applying even a mere point of zinc to a sheet of 

 copper in a saline solution) was so very great as actually to 

 impede the sailing of the vessel. This appears to have been 

 considered a fatal objection to the application of his impor- 

 tant discovery — as it has never been acted on in more than 

 two or three cases — although it is sufficiently obvious that 

 methods could readily be contrived for removing accumula- 

 tions of the nature in question from the bottom. If copper 

 protectors were used, not only would a great saving accrue 

 to the country but likewise to the interests of humanity. 



In June, 1824, Sir Humphry Davy made an excursion to 

 Norway, and through Sweden, Denmark, Holstein and 

 Hanover. During this tour he met with several distinguished 

 men of science, whom he particularly notices. At Bremen 

 he "dined with Dr. Olbers, and saw with much pleasure 

 the telescope with which he discovered his two new planets, 

 and met Gauss. Olbers gave us an excellent dinner, 

 and is a most amiable and enlightened philosopher ; I spent 

 a very pleasant day." *' I am rejoiced that I made the 

 excursion to Altona and Bremen : it has given me a better 

 idea of human nature ; for Schumacher, Olbers and Gauss 

 appear to me no less amiable as men than distinguished as 

 philosophers, and they have all the simplicity, goodness of 

 heart and urbanity of manners, which ought to make us 

 proud of their name and of the influence of intellect, and 

 scientific pursuits upon the morals, the habits, and the 



