Salomon de Caus, a native of Normandy, is sometimes claimed by French writers to have first thought of using steam as a motive power in 1615, but his invention does not seem to have fructified. Half a century later the unlucky Doctor Denis Papin, a native of Blois, entered the field of invention. He came to this country from France in 1675, was elected a Fellow of the Royal Society in 1681, and in 1690 described a steam cylinder fitted with a piston which descended by atmospheric pressure when the steam below it was condensed. He suggested that one of the uses to which his engine might be put was the revolution of paddle-wheels fitted to a ship, several cylinders being applied which worked alternately with the rackwork he designed. He may have been led to this by witnessing in 1681 the experiments on the Thames with a boat designed by Rupert, the Prince Palatine, with revolving fans, which easily left behind a boat manned by a number of oarsmen. It has been claimed for Papin that he was the inventor of the safety-valve, but this is disputed.[7] Prior, however, to his atmospheric engine he brought out in 1685 a machine for raising or pumping water, but the Royal Society treated it with contempt and referred to it as a “mere trick.” Neither of his machines received the recognition which historians have since decided was their due, and he went back disheartened to France, whence he was driven by the Revocation of the Edict of Nantes to Marburg. He reappeared in England in 1707 and announced a project for moving ships by means of wheels and steam. Unfortunately for him, Thomas Savery, born in 1658, had already been at work on the problem, and had brought out his fire-engine, which among other things he thought might be used to propel ships. His machine lacked power, and was replaced by one made after the design of his partner Newcomen. Papin was also associated with Newcomen and Savery at one time. Savery says of his own machine that he would refer the question of its suitability for shipping to those more competent than himself to judge. Papin appealed to the Naval Department to consider his invention, but the Government of the day, after the manner of Governments when face to face with a new project, thought it useless, and made severe remarks on his presumption in continuing to invent for them. He exhibited his invention on the Thames, but no one took any interest in it. Thoroughly disheartened by the failures which attended all his efforts, Papin went to Germany, and is stated to have there built a steamer which was actually tried on the Fulda or the Weser, but the local watermen, fearing the rivalry of the new machine, smashed it, and that is the last which history has to record of Papin as a pioneer of steamboats. It is asserted that this boat was built for him by Newcomen and Savery in this country. As an experimenter he did valuable work, for he seems to have been the first to have grasped the importance of the vacuum under the piston.[8]