It is possible that, in some cases, in consequence of the sheets not having been properly cleansed before they are rolled, a portion of the oxide may be pressed into them by the rollers. In such a case, a Voltaic effect might be produced, and portions of the metallic surface rendered more electro-positive. The President and Council of the Royal Society appear to have been swayed by this consideration, when they adjudged to him "A Royal Medal,[100] for his Bakerian Lecture on the relations of electrical changes, considered as the last link, in order of time, of the splendid chain of discoveries in chemical electricity, which have been continued for so many years of his valuable life." [100] In the year 1825, His Majesty George IV. communicated to the Royal Society, through Mr. Peel, his intention to found two gold medals, of the value of fifty guineas each, to be awarded annually by the Council of the Royal Society, in such a manner as shall, by the excitement of competition among men of science, seem best calculated to promote the object for which the Royal Society was instituted. Thus had Davy now received from the Royal Society all the honours they were capable of conferring upon him. In the year 1805, they adjudged to him the medal on Sir Godfrey Copley's donation for his various communications published in the Philosophical Transactions; in 1817, they awarded him the Rumford medals for his papers on combustion and flame; and in 1827, upon the grounds just stated, the President and Council expressed their unabated admiration by conferring upon him the only medal which remained for his acceptance--that which had been recently founded by their patron, his late Majesty. Having thus disposed of the speculative part of his admirable enquiry, it will be interesting to pause in our narrative, in order to take a philosophical review of the progress of Voltaic discovery, in its relations to this particular object. It is a subject well calculated to afford a valuable lesson to the experimentalist, and at the same time to furnish illustrations, more striking even than that of the safety-lamp, of the necessity of that complicated species of machinery, without which the human mind is frequently unable to grapple with the simplicities of truth. It is true, that the fact of a galvanic effect being excited by the contact of two dissimilar metals was noticed in the earliest stages of the enquiry, but it is equally evident that the phenomena which attended it, and the laws by which it was directed, required for their discovery and elucidation the assistance of the Voltaic battery. In reference to Davy, it may be here repeated, that the power of obtaining simple results, through complicated means, was one of the most distinguishing features of his genius.