(Act of June 10, 1898, ch. 423, 30 Stat. L. 440.) Section 1. Classification of Letters Patent and Printed Publications. That for the purpose of determining with more readiness and accuracy the novelty of inventions for which applications for letters patent are or may be filed in the United States Patent Office, and to prevent the issuance of letters patent of the United States for inventions which are not new, the Commissioner of Patents is hereby authorized and directed to revise and perfect the classification, by subjects-matter, of all letters patent and printed publications in the United States Patent Office which constitute the field of search in the examination as to the novelty of invention for which applications for patents are or may be filed.

Section 2. Additional Employes. That for the purpose of enabling the Commissioner of Patents to carry out the provisions of this act, the Secretary of the Interior is hereby authorized to appoint from time to time, in the manner already provided by law, such additional number of principal examiners, assistant examiners, first-class clerks, copyists, laborers, assistant messengers, and messenger boys as he may deem necessary; provided, however, that the whole number of additional employes shall not exceed three principal examiners, two first assistant examiners, two second assistant examiners, six third assistant examiners, five fourth assistant examiners, four first-class clerks, four copyists, six laborers, six assistant messengers, and six messenger boys; that the annual expenses for this additional force shall not exceed the sum of $62,880.

Patents, how Issued, Attested, and Recorded.

Section 4883. All patents shall be issued in the name of the United States of America, under the seal of the Patent Office, and shall be signed by the Commissioner of Patents, and they shall be recorded, together with the specifications, in the Patent Office, in books to be kept for that purpose.

A patent is a contract and its construction is governed by the same canons of interpretation that control the construction of other grants and agreements.4 Congress, having created the monopoly, may put such limitations upon it as it pleases.5 A patent is void unless all the statutory requisites are complied with.6 The United States may maintain a suit in equity to cancel a patent obtained by fraud, mistake or accident.7

4 National Hollow Brake Beam Co. vs. Interchangeable Brake Beam Co., 106 Fed. Rep., 693.

5 Most vs. Stover Mfg. Co., 177 U.

S., 483-6 Roener vs. Simon, 95.U. S., 214.