1. REQUISITES AND TERM OF CAVEAT.-Any citizen of the United States who shall have made any new invention or discovery, and shall desire further time to mature the same, may, on payment of the duty required by law, ($10,) file in the Patent Office a caveat, setting forth the design thereof, and of its distinguishing characteristics, and praying protection of his right until he shall have matured his invention; and such caveat shall be filed in the confidential archives of the office and preserve in se 207 crecy, and shall be operative for the term of one year from the filing thereof. (Act of July 8, 1870, § 40.) 2. PROCEEDINGS IN CASE OF AN INTERFERING APPLICATION.-If application shall be made within the year by any other person for a patent with which such caveat would in any manner interfere, the Commissioner shall deposit the description, specification, drawings, and model of such application in like manner in the confidential archives of the office, and give notice thereof, by mail, to the person filing the caveat, who, if he would avail himself of his caveat, shall file his description, specifications, drawings, and model within three months from the time of placing said notice in the post office in Washington, with the usual time required for transmitting it to the caveator added thereto, which time shall be indorsed on the notice. (Ib.) 3. WHEN AN ALIEN MAY FILE A CAVEAT.-An alien shall have the privilege of filing a caveat if he shall have resided in the United States one year next preceding the filing of his caveat, and made oath of his intention to become a citizen. (Ib.) 4. NO NOTICE GIVEN OF PENDING APPLICATIONS.-The caveator will not be entitled to notice of any application pending at the time of filing his caveat, nor of any application filed after the expiration of one year from the date of filing the caveat. (Patent Office Rules, July, 1870.) 5. RENEWAL.-The caveator may renew his caveat at the end of one year by paying a second caveat fee of $10, which will continue it in force for one year longer, and so on from year to year as long as the caveator may desire. (Ib.) 6. DESCRIPTION.—A caveat need not contain as partic ular a description of the invention as is requisite in a specification; but still the description should be sufficiently precise to enable the office to judge whether there is a probable interference when a subsequent application is filed. (Ib.) It is to set forth the "design and purpose" of the invention and its "distinguishing characteristics;" but it is not necessary that it should explain the principle involved, or the modes in which it can be applied, nor how it is distinguished from other inventions. (11 Opinions of Attorneys General, 65.) Nor is it necessary to accompany the caveat with specimens of ingredients, or compounds, or model. (Ib.) It is not required to be specific in its terms, nor is it presumed to describe the whole invention of the party but is filed in the office rather as a warning that the in ventor is in the exercise of due diligence in the pursui and perfection of his discovery. (Collins v. White, MS Appeal Cases, D. C., 1860.) 7. DRAWINGS.-When practicable, the caveat must be accompanied by drawings or sketches. (Patent Office Rules, July, 1870.) 8. PURPOSE OF CAVEAT.-A caveat answers a double purpose: first, to give notice of the inventor's claim; and, second, to prevent a patent from issuing to another for the same thing. (Allen v. Hunter, 6 McLean, 304.) Its office is to save the discoverer of an invention from the effect of the rule of law, that gives to the inventor who first adapts his invention to practical use the right to the grant of a patent; and if the Commissioner complies with the terms of § 12 of the act of 1836, as to giving the caveator notice of any interfering application, |