Where an inventor has completed his invention, if he neither applies for a patent nor puts it to practical use. a subsequent inventor who promptly applies is entitled to the patent, and the first one is deemed to have abandoned his rights. Pattee v. Russell, 3 O. G., 181; Ex parte Carre, 5 O. G., 30; Johnson v. Root, 1 Fisher, 351.

As between two rival inventors, the test of priority is the diligence of the one first to conceive it. If he has been diligent in perfecting it, he is entitled to receive the patent. If he has been negligent, the patent is awarded to his opponent. Robinson on Patents. Sec. 375.

The construction and use in public of a working machine, whether the inventor has or has not abandoned it, excludes the grant of a patent to a subsequent inventor. An abandonment in such case inures to the benefit of the public and not to the benefit of a subsequent inventor. Young v. Van Duser, 16 O. G., 95.

A mere aggregation or combination of old devices is not patentable when the elements are unchanged in function and effect. They are patentable when, "by the action of the elements upon each other, or by their joint action on their common object, they perform additional functions and accomplish additional effects." Robinson on Patents, Sec. 154.

A change of shape enabling an instrument to perform new functions is invention. Wilson v. Coon, 18 Blatch. 532; Collar Co. v. White, 7 O. G., 690, 877.

A patent which is simply for a method of transacting business or keeping accounts is not valid. U. S. Credit System Co. v. American Indemnity Co., 63 O. G., 318.

The law requires that manufacturers of patented articles give notice to the public that the goods are patented by marking thereon the date of the patent or giving equivalent notice. When this law is not complied with, only nominal damages can be recovered. Wilson v. Singer Mfg. Co., 4 Bann. & A. 637; McCourt v. Brodie. 5 Fisher, 384.

To prevent fraudulent impositions on the public it is forbidden that unpatented articles be stamped "Patented," and where this is done with intention to deceive, a penalty of one hundred dollars and costs for each article so stamped is provided. Any person may bring action against such offenders. Walker v. Hawxhurst, 5 Blatch. 494; Tompkins v. Butterfield, 25 Fed. Rep. 556.

A patentee is bound by the limitations imposed on his patent, whether they are voluntary or enforced by the Patent Office, and if he accepts claims not covering his entire invention he abandons the remainder. Toepfer v. Goetz, 41 O. G., 933.

Claims should be construed, if possible, to sustain the patentee's right to all he has invented. Ransom v. Mayor of N. Y. (1856), Fisher, 252.

The assignor of a patented invention is estopped from denying the validity of his own patent or his own title to the interest transferred. He cannot become the owner of an older patent and hold it against his assignee. Robinson on Patents, Sec. 787, and notes.

Any assignment which does not convey to the assignee the entire and unqualified monopoly which the patentee holds in the territory specified, or an undivided interest in the entire monopoly, is a mere license. Sanford v. Messer, 2 O. G., 470.