In the early part of the reign of Edward the Third, the French introduced cannon on board their ships, chiefly in consequence of which his fleet, under the young Earl of Pembroke, as I have described, was defeated before Rochelle. He took care, however, that this should not again occur, and by the year 1338 he appears to have introduced them on board most of his ships, and by the end of his reign no ships of war were without them. Their employment, of course, effected a great change in naval warfare, but a far greater revolution was about to take place in the whole system of navigation, by the introduction of the mariner's compass. I have before stated that if not discovered it was at all events improved by Flavio Gioja, of Amain, in the kingdom of Naples, about A.D. 1300. It was soon discovered that the needle does not point, in all places, truly to the North Pole, but that it varies considerably in different degrees of longitude, and this is called the variation of the needle. It has also another variation, called the declination, or dip. The cause of these phenomena is still utterly unknown. The means of steering with almost perfect accuracy across the pathless ocean, gave a confidence to mariners, when they lost sight of land, which they had never before possessed, and in time induced them to launch forth in search of new territories in hitherto unexplored regions. The English were, however, too much occupied with foreign wars or domestic broils to attend much to navigation. We hear of a certain Nicholas of Lynn, a friar of Oxford, who, A.D. 1360, just sixty years after the use of the compass became known, sailed in charge of certain ships to visit and explore all the islands to the north of Europe. He, it is said, returned and laid before King Edward the Third an account of his discoveries in those northern regions, but what they were or what benefit resulted from them, history does not tell us. Father Nicholas's knowledge of navigation was probably somewhat limited and not very practical, and it is just probable that his voyage was not so extensive as it was intended to be; but that, having the pen of a ready writer, he drew on his imagination for a description of the countries he was supposed to have surveyed. At all events, we hear of no voyage undertaken at the sovereign's instigation till nearly two centuries later.