M. Poppe of Tuebingen tells of a clock made by M. Geiser, which was an admirable piece of mechanism and seemed to have solved this great problem in an ingenious and simple manner, but it deceived only for a time. When thoroughly examined inwardly and outwardly, some time after his death, it was found that the center props supporting its cylinders contained cleverly constructed, hidden clock-work, wound up by inserting a key in a small hole under the second-hand. Another case was that of a man named Adams who exhibited, for eight or nine days, his pretended perpetual motion in a town in England and took in the natives for fifty or sixty pounds. Accident, however, led to a discovery of the imposture. A gentleman, viewing the machine took hold of the wheel or trundle and lifted it up a little, which probably disengaged the wheels that connected the hidden machinery in the plinth, and immediately he heard a sound similar to that of a watch when the spring is running down. The owner was in great anger and directly put the wheel into its proper position, and the machine again went around as before. The circumstance was mentioned to an intelligent person who determined to find out and expose the imposture. He took with him a friend to view the machine and they seated themselves one on each side of the table upon which the machine was placed. They then took hold of the wheel and trundle and lifted them up, there being some play in the pivots. Immediately the hidden spring began to run down and they continued to hold the machine in spite of the endeavors of the owner to prevent them. When the spring had run down, they placed the machine again on the table and offered the owner fifty pounds if it could then set itself going, but notwithstanding his fingering and pushing, it remained motionless. A constable was sent for, the impostor went before a magistrate and there signed a paper confessing his perpetual motion to be a cheat. In the "Mechanic's Magazine," Vol. 46, is an account of a perpetual motion, constructed by one Redhoeffer of Pennsylvania, which obtained sufficient notoriety to induce the Legislature to appoint a committee to enquire into its merits. The attention of Mr. Lukens was turned to the subject, and although the actual moving cause was not discovered, yet the deception was so ingeniously imitated in a machine of similar appearance made by him and moved by a spring so well concealed, that the deceiver himself was deceived and Redhoeffer was induced to believe that Mr. Lukens had been successful in obtaining a moving power in some way in which he himself had failed, when he had produced a machine so plausible in appearance as to deceive the public. Instances of a similar kind might be multiplied indefinitely.