"I think that may often be said of what we call Inventions and what we call Discoveries," he said, "till quite recent times. When a man invented a new process, it was supposed that if he could keep the secret, it might be to him a very valuable secret. But when one discovered an island or a continent, it was almost impossible to keep the secret. They tried it sometimes, as you know. But there must be a whole ship's crew who know something of the new-found land, and from some of them the secret would leak out. "But there has been many a process in the arts lost, because the man who discovered the new quality in nature or invented the new method in manufacture kept it secret, so that he might do better work than his competitors. This went so far that boys were apprenticed to masters to learn 'the secrets of their trades.'" Fergus said that in old times inventors were not always treated very kindly. If people thought they were sorcerers, or in league with the Devil, they did not care much for the invention. Uncle Fritz said they would find plenty of instances of the persecution of inventors, even to quite a late date. It is impossible, of course, to say how many good things were lost to the world by the pig-headedness which discouraged new inventions. It is marvellous to think what progress single men made, who had to begin almost at the beginning, and learn for themselves what every intelligent boy or girl now finds ready for him in the Cyclopædia. It is very clear that the same beginnings were made again and again by some of the early inventors. Then, what they learned had been almost forgotten. There was no careful record of their experiments, or, if any, it was in one manuscript, and that was not accessible to people trying to follow in their steps. "I have laid out for you," said Uncle Fritz, "some of the early accounts of Friar Bacon,--Roger Bacon. He is one of the most distinguished of the early students of what we now call natural philosophy in England. It was in one of the darkest centuries of the Dark Ages. "But see what he did.