The inventor must apply to the commissioner of patents for letters patent which secure to him his invention. The application comprises a petition, specification, claims, oath, drawings if the nature of the invention may be thus shown, and a model, when this is required by the patent office. A fee of fifteen dollars also must be sent with the papers. The application must be signed by the inventor and two witnesses.
The specification is the written description of the invention and of the manner and process of making, constructing, compounding, and using the invention; whatever it may be. He must describe not merely the principle of the invention, but the mode of applying it in such a clear, intelligible manner that those who are "skilled in the art" can, without other aid, use the invention. Nothing should be left to experiment. The phrase "skilled in the art" means persons of ordinary skill. Whether a description is clear, exact and sufficient is a question for the jury whenever it is a matter of legal contention.
In describing an improvement the same rule is applied. The description should show clearly the nature of it. The description should distinguish between the old and the new. "A description in a patent for an improvement is sufficient if a practical mechanic acquainted with the construction of the old machine in which the improvement is made, can, with the aid of the patent and diagram, adopt the improvement." If an inventor intentionally conceals facts or misleads the public by an erroneous description, his patent is void.
Concerning the claim or claims with which the inventor concludes his specification many questions have arisen. First, the claim must be clearly stated so that the public may know what it is. The claim should not be too broad. Several claims may be made, but they should not be varying phraseology for the same thing. They should state the physical structure or elements of mechanism by which the end or result is produced.
The inventor must make oath that he believes himself to be the original and first inventor, that he does not believe that the thing was ever before known or used, and as to his citizenship. If dead or insane, the oath must be made by his executor, administrator, or other representative. After the application is granted another fee of twenty dollars must be paid.