That Perpetual Motion Idea.

New York Times 100 years ago today, February 16, 1913:
    For a hundred years after the establishment of the Patent Office at Washington every applicant for a mechanical patent was compelled to file, with his application, a practical working model of his invention. The result was that in the early nineties of the last century the great building devoted to this bureau had become packed lo the ceiling with hundreds of thousands of models, making the due dispatch of business almost impossible. About that time some curious delver among old models found one of a stump-extractor, which contained a vial of nitroglycerine. The patentee had literally followed instructions and put real "working" nitroglycerine in the model! This incident precipitated an immediate change of rule. Wherefore, since that time — about twenty years ago — not only are models not demanded of applicants for invention, but they will not even be received in the Patent Office.
    There is one notable exception to this rule, however. That is in the case of applications for inventions which claim the discovery of perpetual motion. In this single exception not only does the Patent Office insist upon a working model, but the application will not be considered until such working model is exhibited to the satisfaction of the officials of the office.
    "There have, in the past twenty years, been scores of would-be applicants for patents upon perpetual motion inventions," said the Examiner of Patents, under whose special department these inventions come, "but none of them have brought their models with them. When they have been told that a working model was necessary before their applications could be considered they have invariably exclaimed confidently, 'Why, certainly, I will make a working model and bring it around next week' — or next month, maybe — 'and exhibit it to your special satisfaction.' "Come back?" continued the official. "No, none of them have ever come back. The greatest scientists of the world consider that perpetual motion is impossible, and not only our reason, but our experience here has taught us to believe like them. Of course, by perpetual motion is meant a machine that will continue to run indefinitely without receiving motive power from any outside source. Such a machine is scientifically imposable — therefore we require a working model here!"