construction of words used in the patent, and in the specification. It was held, as we have seen, that an engine might be described as a method of lessening the consumption of fuel and steam in fire-engines. In the specification, the invention was said to consist of the following principles, and the patentee then proceeded to describe the machinery and apparatus for which he claimed a patent, thus defining what he meant by principles, and though the word was thus used in an unusual sense, and inaccurately, yet as the sense in which it was used was apparent from the specification, this was held to be no ground of objection. So Lord Ellenborough remarked, in another case, that if a term used in the specification had a meaning annexed to it by the usage of trade, different from its ordinary use, it might be received in the peculiar perverted sense.15

14

Technical words are often used in patents and specifications, and sometimes it is not practicable to describe an invention without the use of them. And it has been held that words of a foreign language and figures may be introduced into the specification.16

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

14 Boulton v. Bull, 2 H. Bl. 463; Hornblower v. Boulton, 8 T. R. 95. And see Jones v. Pearce, Gods. sup. 16.

15 The King v. Metcalf, 2 Stark, N. P. 249.

16 Bloxam v. Elsee, 1 Car. & P. 558.

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. 17

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. The Patentee must not claim too much.

17 Kneass v. Schuylkill Bank, C. C. U. S. Penn. Oct. 1820, Coxe's Dig. 532.

8. The Specification must direct how to make, and describe the best way known to the Inventor of making the article.

9. Reference in the Specification to Drawings. 10. The consequence of a defect in the Specification.

Sect. 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 that of Great Britain in 1835, passed laws to remedy this evil. These provisions have been mentioned above,' and will be more particularly stated in a subsequent section of the present chapter.*

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 loss. In treating of the specification, the cases and the law will be stated just as if those acts had not been passed, the reader being apprized that for some of the defects, on account of which the patent right would otherwise be defeated, those acts afford a partial remedy, that is, he 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 inflicts 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 un

derstand 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. These two objects of the specification are the foundation of the rules and decisions in regard to it.

The English jurisprudence prescribes one rule on this subject which is not applicable to ours, namely, the one already mentioned, that the specification must agree with the title or patent, for in England the patent is for the title or general description of what is particularly described in the specification, and so also is our patent, but as our law makes the specification a part of the patent, the title or general description may not only be explained, but also controlled and enlarged by the recital of the more particular and full description given in the specification; for if it appear that the patentee has not, in his title, given a correct general description of his invention, but has fully and accurately described it in the specification, he ought not to lose his privilege on this account, since no wrong is done to the public, and no imposition is practised upon individuals. The case is different in England, as we have already suggested, where the rule that the specification must agree with the patent or title, and cannot enlarge it,

3 Evans v. Eaton, 7 Wheat. 433.

* Supra, p. 225.