and other writings, namely, that where definite and specific, and also very general descriptive terms are used in reference to the same subject matter, the meaning of the latter may be modified and restrained by the former. This is illustrated in the case of a patent for "an apparatus for extracting inflammable gas by heat, from pit-coal, tar, or any other substance, from which gas or gasses, capable of being employed for illumination, can be extracted by heat." It was proved that the apparatus would not succeed in making gas from oil, and it was objected to the patent that there was nothing to prevent a person, who saw the specification, from considering that it was meant to be included, and so that the specification covered more ground than the invention, and was not true, and that accordingly the patent was void. But Lord Tenterden ruled that the phrase "any other substance must be construed to be applicable to substances of the same sort, (ejusdem generis), with those enumerated, and so that the description was sufficiently accurate, and the patent valid. A mistake in the use of one word for another, so as either to pervert the sense, or make nonsense, may be rectified in the case of a patent as well as in other written instruments, by other parts of the document. Thus, where the word painting was used by mistake. in the patent for the word printing, Mr. Justice Washington held that the error might be corrected by other parts of the patent and the specification.13 CHAPTER XI. Specification. Sec. 1. Leading Objects in the Specification. Distinction between English and American Patents as to the Specification. 2. General Requisites. 3. Known Processes, Methods and Machinery need not be described. Surplusage. 4. The Specification is addressed to Artists. Technical Terms. 5. Must be true and not mislead. 6. Must be full, clear, and exact. 7. What is claimed as new must be distinguished from what is old. not claim too much. The Patentee must 8. The Specification must direct how to make, and describe the best way known to the Inventor of making the article. 13 Kneass V. Schuylkill Bank, C. C. U. S. Penn. Oct. 1820, Coxe's Dig. 532. 9. Reference in the Specification to Drawings. 10. The consequence of a defect in the Specifica tion. Sec. I.-LEADING OBJECTS IN THE SPECIFICATION. DISTINCTION BETWEEN ENGLISH AND AMERICAN PATENTS AS TO THE SPECIFICATION. THE specification is no less important than the invention itself, and the instances of patents being declared void by the courts on account of the defects of the specification, are probably quite as many as those of failure from the insufficiency of the invention.' It requires no little skill and knowledge of the subject of the invention, to draw up an adequate and apt specification. And skill and knowledge of the subject will not suffice for this purpose, without also a knowledge of the law of patents generally. The frequent failure of patents in consequence of defects in the specification through inadvertency, has heretofore been a subject of loud complaint, both in England and the United States, until the legislatures of both countries, that of the United States in 1832, and again in 1836, and that of Great Britain in 1835, passed laws to remedy this evil. The statement of Benjamin Rotch, Esq., Rep. of Com. of Brit. H. of Com. 1829, p. 108. The patentee may, by availing himself of the remedy thus provided, avoid the absolute loss of his monopoly, on account of those defects in the specification which were before the frequent occasion of its forfeiture. In treating of the specification, the cases and the law will be stated just as if those provisions had not been made, the reader being apprized that for some of the defects, on account of which the patent right would otherwise be defeated, those provisions afford a partial remedy, that is, the patentee does not absolutely lose his privilege, provided he takes advantage of the provisions thus made in his favor. There are two objects in view in making a specification. As the law grants the patentee a monopoly, and not only awards damages, but provides for a penalty for a violation of the exclusive privilege, it very equitably requires that the invention shall be so described in the specification, that every person may, by examining it, know what the patentee claims, and be able to distinguish what may be an infringement. The other object of the specification is to give the public the advantage of the invention after the expiration of the patent. The consideration of the patent being the advantage to be derived to the public after its expiration, it is necessary, in order that this advantage may be realized, that the invention shall so be described in the specification, that one acquainted with the art or manufacture, to which it relates, or with which it is most nearly connected, may not only understand the invention, but be able, by following the directions given in the specification, with the assistance of the drawings, to construct the machine or perform the process which is the subject of the patent.2 These two objects of the specification are the foundation of the rules and decisions in regard to it. Sec. II.-GENERAL REQUISITES OF THE SPECI FICATION. The general requisites of a specification were given in the patent act of 1793, s. 3, which is very nearly followed by section 6 of that of 1836, by which it is provided that "every inventor, before he can receive a patent, shall deliver a written description of his invention, and of the manner and process of making, constructing, using, and compounding the same, in such full, clear, and exact terms, avoiding all unnecessary prolixity, as to distinguish it from all other things before known, and to enable any person, skilled in the art or science, to which it appertains or with which it 2 Evans v. Eaton, 7 Wheat. 433. |